libglusterfs: wrong function definition of synclock_destory(). 

synclock_destory() has been prototyped in syncop.h,
how-ever synclock_destroy() is the actual function used in syncop.c.
Correcting this function definition along with few typos.


Change-Id: I35a818190c1d37c303279ca7a820f01895751bd9
BUG: 1075417
Signed-off-by: Humble Chirammal <hchiramm@redhat.com>
Reviewed-on: http://review.gluster.org/8266
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-by: soumya k <skoduri@redhat.com>
Reviewed-by: Poornima G <pgurusid@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>