Patch by Kenneth Loafman <kenneth@loafman.com> for duplicity <= 0.4.12 to solve scp syntax
regression introduced with duplicity 0.4.12. Problem is, that user@hostname:port works, but
hostname:port doesn't any longer. This patch solves the behaviour and will be included into
the next upstream release as well. For further information, see:

 - https://savannah.nongnu.org/bugs/index.php?23988
 - https://bugzilla.redhat.com/show_bug.cgi?id=457680

--- duplicity-0.4.12/src/backends.py			2008-07-22 17:20:04.000000000 +0200
+++ duplicity-0.4.12/src/backends.py.scp_username	2008-08-03 19:58:35.000000000 +0200
@@ -330,8 +330,11 @@
 						   "You can get pexpect from http://pexpect.sourceforge.net or "
 						   "python-pexpect from your distro's repository.")
 		
-		# host string of form user@hostname:port
-		self.host_string = parsed_url.username + "@" + parsed_url.hostname
+		# host string of form [user@]hostname
+		if parsed_url.username:
+			self.host_string = parsed_url.username + "@" + parsed_url.hostname
+		else:
+			self.host_string = parsed_url.hostname
 		# make sure remote_dir is always valid
 		if parsed_url.path:
 			# remove leading '/'