Renaming hash bucket locking functions

1. new abbreviated previx: ocf_hb (HB stands for hash bucket)
2. clear distinction between functions requiring caller to
   hold metadata shared global lock ("naked") vs the ones
   which acquire global lock on its own ("prot" for protected)
3. clear distinction between hash bucket locking functions
   accepting hash bucket id ("id"), core line and lba ("cline")
   and entire request ("req").

Resulting naming scheme:
ocf_hb_(id/cline/req)_(prot/naked)_(lock/unlock/trylock)_(rd/wr)

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>

src/metadata/metadata_collision.c

@@ -304,6 +304,7 @@ void ocf_metadata_remove_from_collision(struct ocf_cache *cache,
 			OCF_CORE_MAX, ULLONG_MAX);
 }
 
+/* must be called under global metadata read(shared) lock */
 void ocf_metadata_start_collision_shared_access(struct ocf_cache *cache,
 		ocf_cache_line_t line)
 {
@@ -316,6 +317,7 @@ void ocf_metadata_start_collision_shared_access(struct ocf_cache *cache,
 	ocf_collision_start_shared_access(&cache->metadata.lock, page);
 }
 
+/* must be called under  global metadata read(shared) lock */
 void ocf_metadata_end_collision_shared_access(struct ocf_cache *cache,
 		ocf_cache_line_t line)
 {