Build(deps): Bump ubuntu from `99c3519` to `278628f` in /docker/exodus #929

Job	Run time
build-deps (gnu, 4.9.2)	28s
build-deps (clang, 4.9.2)	39s
build-deps (mpi, 4.9.2)	33s
Debug serial build	4m 22s
Debug parallel build	4m 56s
Use modern CMake configure of netCDF package	6m 20s
	17m 18s

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