[master] fix case in acronym

(noticed when another fix was suggested for same line)

src/lib/dhcpsrv/dhcpsrv_messages.mes

@@ -212,7 +212,7 @@ with the specified address to the MySQL backend database.
 A debug message issued when the server is about to add an IPv6 lease
 with the specified address to the MySQL backend database.
 
-% DHCPSRV_MYSQL_COMMIT committing to MySQl database
+% DHCPSRV_MYSQL_COMMIT committing to MySQL database
 The code has issued a commit call.  All outstanding transactions will be
 committed to the database.  Note that depending on the MySQL settings,
 the commital may not include a write to disk.