Do not validate relevant user name

- This makes Special:Log's behaviour consistent with other special
  pages, e.g. Special:Contributions.

Change-Id: Ic0a9322d920d7514bacac1f29a1da4fe57cae854

includes/logging/LogPager.php

@@ -384,6 +384,8 @@ class LogPager extends ReverseChronologicalPager {
 	}
 
 	/**
+	 * Guaranteed to either return a valid title string or a Zero-Length String
+	 *
 	 * @return string
 	 */
 	public function getPerformer() {

includes/specials/SpecialLog.php

@@ -187,7 +187,8 @@ class SpecialLog extends SpecialPage {
 
 		# Set relevant user
 		if ( $pager->getPerformer() ) {
-			$this->getSkin()->setRelevantUser( User::newFromName( $pager->getPerformer() ) );
+			$performerUser = User::newFromName( $pager->getPerformer(), false );
+			$this->getSkin()->setRelevantUser( $performerUser );
 		}
 
 		# Show form options