git: Ensure in right srcdir if a fallback to git-clone happens.

This apparently worked accidentally in most cases but it doesn't
interact well with options like 'remove-after-install' from previous
module builds.

modules/ksb/Updater/Git.pm

@@ -86,6 +86,7 @@ sub clone
     if ((my $e = had_an_exception()) || !$result) {
         warning($e->message()) if $e;
         note ("\tFalling back to clone of $module");
+        p_chdir($srcdir);
         if (0 != log_command($module, 'git-clone', ['git', 'clone', @args])) {
             croak_runtime("Failed to make initial clone of $module");
         }
@@ -96,8 +97,6 @@ sub clone
 
     my ($commitId, $commitType) = $self->_determinePreferredCheckoutSource($module);
 
-    p_chdir($srcdir);
-
     # Switch immediately to user-requested tag or branch now.
     if ($commitType eq 'tag') {
         info ("\tSwitching to specific commit g[$commitId]");