Fix bzr plugin to work with bzr 2.0.

The output of "bzr log" seems to have changed a bit, so we change the
parsing accordingly. This has not been tested with earlier versions of
bzr.

Several problems seemed to occur, all in the bzr_log subroutine:

1. The @infos list would contain an empty hash, which would confuse the
   rest of the program.
2. This was because bzr_log would push an empty anonymous hash to the
   list whenever it thought a new record would start.
3. However, a new record marker (now?) also happens at th end of bzr log
   output.
4. Now we collect the record to a hash that gets pushed to the list only
   if it is not empty.
5. Also, sometimes bzr log outputs "revno: 1234 [merge]", so we catch only
   the revision number.
6. Finally, there may be non-headers at the of the output, so we ignore
   those.

IkiWiki/Plugin/bzr.pm

@@ -73,28 +73,37 @@ sub bzr_log ($) {
 	my @infos = ();
 	my $key = undef;
 
+    my $hash = {};
 	while (<$out>) {
 		my $line = $_;
 		my ($value);
 		if ($line =~ /^message:/) {
 			$key = "message";
-			$infos[$#infos]{$key} = "";
+			$$hash{$key} = "";
 		}
 		elsif ($line =~ /^(modified|added|renamed|renamed and modified|removed):/) {
 			$key = "files";
-			unless (defined($infos[$#infos]{$key})) { $infos[$#infos]{$key} = ""; }
+			unless (defined($$hash{$key})) { $$hash{$key} = ""; }
 		}
 		elsif (defined($key) and $line =~ /^  (.*)/) {
-			$infos[$#infos]{$key} .= "$1\n";
+			$$hash{$key} .= "$1\n";
 		}
 		elsif ($line eq "------------------------------------------------------------\n") {
-			$key = undef;
-			push (@infos, {});
+		    if (keys %$hash) {
+    		    push (@infos, $hash);
 		    }
-		else {
+    		$hash = {};
+			$key = undef;
+		}
+		elsif ($line =~ /: /) {
 			chomp $line;
+			if ($line =~ /^revno: (\d+)/) {
+			    $key = "revno";
+			    $value = $1;
+			} else {
     			($key, $value) = split /: +/, $line, 2;
-			$infos[$#infos]{$key} = $value;
+    		}
+			$$hash{$key} = $value;
 		} 
 	}
 	close $out;