common: make all calls to pthread_*() uniform

1) Make all calls to pthread_*() uniform:
   - *_lock() - set errno to return value, call LOG() and error out,
   - *_unlock() and *_init() - set errno to return value and call LOG()
2) Change return type of lane_exit() to static void.
Merge pull request #39 from ldorau/blk-check-return-pthread_mutex_lock

common: make all calls to pthread_*() uniform