Fix CS issues

Author: willemstuursma

classes/mutex/MySQLMutex.php

@@ -62,7 +62,7 @@ public function lock()
             throw new LockAcquireException("An error occurred while acquiring the lock");
         }
 
-        throw new TimeoutException("The attempt timed out (for example, because another client has previously locked the name)");
+        throw new TimeoutException("Timeout when acquiring lock.");
     }
 
     public function unlock()
@@ -72,4 +72,4 @@ public function unlock()
             $this->name
         ]);
     }
-}
+}