Get default branch name from the right git dir

Author: swissspidy

.maintenance/refresh-repository.php

@@ -10,7 +10,7 @@
 printf( "--- Refreshing repository \033[32m{$repository}\033[0m ---\n" );
 
 printf( "Switching to latest \033[33mdefault\033[0m branch...\n" );
-system( "git --git-dir={$path}/.git --work-tree={$path} checkout $(git remote show origin | grep 'HEAD branch' | cut -d' ' -f5)" );
+system( "git --git-dir={$path}/.git --work-tree={$path} checkout $(git --git-dir={$path}/.git remote show origin | grep 'HEAD branch' | cut -d' ' -f5)" );
 
 printf( "Pulling latest changes...\n" );
 system( "git --git-dir={$path}/.git --work-tree={$path} pull" );