annotate: Support annotation of files on other revisions.

This is a bug fix, and cleans up one or two other things spotted during the
course of tracking down the main bug here.

[jc: the part that updates test-suite is split out to the next
 one. Also I dropped "use Data::Dumper;" which seemed leftover
 from debugging session.]

Signed-off-by: Ryan Anderson <ryan@michonline.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-annotate.perl

@@ -99,7 +99,7 @@ ()
 	}
 }
 push @revqueue, $head;
-init_claim( defined $starting_rev ? $starting_rev : 'dirty');
+init_claim( defined $starting_rev ? $head : 'dirty');
 unless (defined $starting_rev) {
 	my $diff = open_pipe("git","diff","-R", "HEAD", "--",$filename)
 		or die "Failed to call git diff to check for dirty state: $!";
@@ -345,6 +345,7 @@ sub git_cat_file {
 	return () unless defined $rev && defined $filename;
 
 	my $blob = git_ls_tree($rev, $filename);
+	die "Failed to find a blob for $filename in rev $rev\n" if !defined $blob;
 
 	my $catfile = open_pipe("git","cat-file", "blob", $blob)
 		or die "Failed to git-cat-file blob $blob (rev $rev, file $filename): " . $!;
@@ -367,12 +368,13 @@ sub git_ls_tree {
 
 	my ($mode, $type, $blob, $tfilename);
 	while(<$lstree>) {
+		chomp;
 		($mode, $type, $blob, $tfilename) = split(/\s+/, $_, 4);
 		last if ($tfilename eq $filename);
 	}
 	close($lstree);
 
-	return $blob if $filename eq $filename;
+	return $blob if ($tfilename eq $filename);
 	die "git-ls-tree failed to find blob for $filename";
 
 }