[IMP] newrelic: wrap target server initialization

[Shamsidinkhon]

It breaks while exporting odoo translations. odoo-community/odoo-bin -c odoo.conf -d {database_name} --workers=0 --no-http --stop-after-init --i18n-export={export_path} --modules={module_name} -l nl_NL. This PR skips target server initialization if stop-after-init argument is provided

Traceback:

Traceback (most recent call last):
  File "/newrelic/__init__.py", line 19, in <module>
    instrumented = target._nr_instrumented
AttributeError: 'NoneType' object has no attribute '_nr_instrumented'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  ...
    odoo.modules.registry.Registry.new(database, update_module=True)
  File "/odoo-community/odoo/modules/registry.py", line 89, in new
    odoo.modules.load_modules(registry._db, force_demo, status, update_module)
  File "/odoo-community/odoo/modules/loading.py", line 455, in load_modules
    processed_modules += load_marked_modules(cr, graph,
  File "/odoo-community/odoo/modules/loading.py", line 347, in load_marked_modules
    loaded, processed = load_module_graph(
  File "/odoo-community/odoo/modules/loading.py", line 179, in load_module_graph
    load_openerp_module(package.name)
  File "/odoo-community/odoo/modules/module.py", line 385, in load_openerp_module
    __import__('odoo.addons.' + module_name)
  File "/newrelic/__init__.py", line 21, in <module>
    instrumented = target._nr_instrumented = False
AttributeError: 'NoneType' object has no attribute '_nr_instrumented'