(partially) Fix Bug#55227 Fix compiler warnings in innodb with gcc 4.6

Fix compiler warning:
log/log0recv.c: In function 'recv_synchronize_groups':
log/log0recv.c:403:10: error: variable 'limit_lsn' set but not used [-Werror=unused-but-set-variable]

storage/innobase/log/log0recv.c

@@ -400,10 +400,8 @@ recv_synchronize_groups(
 	dulint		start_lsn;
 	dulint		end_lsn;
 	dulint		recovered_lsn;
-	dulint		limit_lsn;
 
 	recovered_lsn = recv_sys->recovered_lsn;
-	limit_lsn = recv_sys->limit_lsn;
 
 	/* Read the last recovered log block to the recovery system buffer:
 	the block is always incomplete */