lock_number_of_rows_locked(): Fix a typo in comment, and make the comments

in lock0lock.c and lock0lock.h identical.  The typo was incorrectly fixed in
r1623.

include/lock0lock.h

@@ -609,7 +609,7 @@ lock_validate(void);
 			/* out: TRUE if ok */
 /*************************************************************************
 Return approximate number or record locks (bits set in the bitmap) for
-this transaction. Since delete-marked records maybe removed, the
+this transaction. Since delete-marked records may be removed, the
 record count will not be precise. */
 
 ulint