git-remote-mediawiki: properly deal with invalid remote revisions

Some wiki, including https://git.wiki.kernel.org/ have invalid revision
numbers (i.e. the actual revision numbers are non-contiguous). Don't die
when encountering one.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/mw-to-git/git-remote-mediawiki

@@ -910,6 +910,10 @@ sub mw_import_revids {
 	my $last_timestamp = 0; # Placeholer in case $rev->timestamp is undefined
 
 	foreach my $pagerevid (@$revision_ids) {
+	        # Count page even if we skip it, since we display
+		# $n/$total and $total includes skipped pages.
+		$n++;
+
 		# fetch the content of the pages
 		my $query = {
 			action => 'query',
@@ -924,6 +928,11 @@ sub mw_import_revids {
 			die "Failed to retrieve modified page for revision $pagerevid";
 		}
 
+		if (defined($result->{query}->{badrevids}->{$pagerevid})) {
+			# The revision id does not exist on the remote wiki.
+			next;
+		}
+
 		if (!defined($result->{query}->{pages})) {
 			die "Invalid revision $pagerevid.";
 		}
@@ -932,10 +941,6 @@ sub mw_import_revids {
 		my $result_page = $result_pages[0];
 		my $rev = $result_pages[0]->{revisions}->[0];
 
-	        # Count page even if we skip it, since we display
-		# $n/$total and $total includes skipped pages.
-		$n++;
-
 		my $page_title = $result_page->{title};
 
 		if (!exists($pages->{$page_title})) {