Avoid cluttering console

[simplyatul]

As mentioned in the issue #45, I updated the code.
Hope this helps.

Post this change, I see following output

sudo ./hello-tail.py
In file included from <built-in>:2:
In file included from /virtual/include/bcc/bpf.h:12:
In file included from include/linux/types.h:6:
In file included from include/uapi/linux/types.h:14:
In file included from include/uapi/linux/posix_types.h:5:
In file included from include/linux/stddef.h:5:
In file included from include/uapi/linux/stddef.h:5:
In file included from include/linux/compiler_types.h:80:
include/linux/compiler-clang.h:41:9: warning: '__HAVE_BUILTIN_BSWAP32__' macro redefined [-Wmacro-redefined]
#define __HAVE_BUILTIN_BSWAP32__
        ^
<command line>:4:9: note: previous definition is here
#define __HAVE_BUILTIN_BSWAP32__ 1
        ^
In file included from <built-in>:2:
In file included from /virtual/include/bcc/bpf.h:12:
In file included from include/linux/types.h:6:
In file included from include/uapi/linux/types.h:14:
In file included from include/uapi/linux/posix_types.h:5:
In file included from include/linux/stddef.h:5:
In file included from include/uapi/linux/stddef.h:5:
In file included from include/linux/compiler_types.h:80:
include/linux/compiler-clang.h:42:9: warning: '__HAVE_BUILTIN_BSWAP64__' macro redefined [-Wmacro-redefined]
#define __HAVE_BUILTIN_BSWAP64__
        ^
<command line>:5:9: note: previous definition is here
#define __HAVE_BUILTIN_BSWAP64__ 1
        ^
In file included from <built-in>:2:
In file included from /virtual/include/bcc/bpf.h:12:
In file included from include/linux/types.h:6:
In file included from include/uapi/linux/types.h:14:
In file included from include/uapi/linux/posix_types.h:5:
In file included from include/linux/stddef.h:5:
In file included from include/uapi/linux/stddef.h:5:
In file included from include/linux/compiler_types.h:80:
include/linux/compiler-clang.h:43:9: warning: '__HAVE_BUILTIN_BSWAP16__' macro redefined [-Wmacro-redefined]
#define __HAVE_BUILTIN_BSWAP16__
        ^
<command line>:3:9: note: previous definition is here
#define __HAVE_BUILTIN_BSWAP16__ 1
        ^
3 warnings generated.
b'   hello-tail.py-2499    [000] .....  6464.246546: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.246701: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.246911: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247366: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247378: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247384: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247389: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247393: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247398: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247403: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247407: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247412: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247417: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.247421: bpf_trace_printk: Another syscall: 321'
b'CPU:0 [LOST 102 EVENTS]'
b'   hello-tail.py-2499    [000] .....  6464.248184: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.248189: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.248189: bpf_trace_printk: Another syscall: 321'
b'   hello-tail.py-2499    [000] .....  6464.248189: bpf_trace_printk: Another syscall: 321'

# Repeated prints of above calls come but it stops in a while.
# If I do sudo ls in another terminal, I see following

b'            bash-2501    [001] .....  6471.837279: bpf_trace_printk: Executing a program'
b'           <...>-2503    [000] .....  6471.847721: bpf_trace_printk: Executing a program'
b'           <...>-2505    [000] .....  6471.854628: bpf_trace_printk: Executing a program'
b'            bash-2507    [001] .....  6471.856390: bpf_trace_printk: Executing a program'
b'           <...>-2506    [000] .....  6471.858664: bpf_trace_printk: Executing a program'