Fix retries in git-cvsimport

Fixed a couple of bugs in recovering from broken connections:

The _line() method now returns undef correctly when the connection
is broken instead of falling off the function and returning garbage.

Retries are now reported to stderr and the eventual partially
downloaded file is discarded instead of being appended to.

The "Server gone away" test has been removed, because it was
reachable only if the garbage return bug bit.

Signed-off-by: Martin Mares <mj@ucw.cz>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-cvsimport.perl

@@ -361,6 +361,7 @@ sub _line {
 			}
 		}
 	}
+	return undef;
 }
 sub file {
 	my($self,$fn,$rev) = @_;
@@ -372,19 +373,15 @@ sub file {
 	$self->_file($fn,$rev) and $res = $self->_line($fh);
 
 	if (!defined $res) {
-	    # retry
+	    print STDERR "Server has gone away while fetching $fn $rev, retrying...\n";
+	    truncate $fh, 0;
 	    $self->conn();
-	    $self->_file($fn,$rev)
-		    or die "No file command send\n";
+	    $self->_file($fn,$rev) or die "No file command send";
 	    $res = $self->_line($fh);
-	    die "No input: $fn $rev\n" unless defined $res;
+	    die "Retry failed" unless defined $res;
 	}
 	close ($fh);
 
-	if ($res eq '') {
-	    die "Looks like the server has gone away while fetching $fn $rev -- exiting!";
-	}
-
 	return ($name, $res);
 }