Merge lp:~yolanda.robla/charm-helpers/fix_add_source into lp:charm-helpers

[Yolanda Robla]

Skip add_source when no source is present

=== modified file 'charmhelpers/contrib/templating/contexts.py'
--- charmhelpers/contrib/templating/contexts.py	2014-02-26 10:35:33 +0000
+++ charmhelpers/contrib/templating/contexts.py	2014-03-03 12:31:59 +0000
@@ -68,7 +68,6 @@
     config['charm_dir'] = charm_dir
     config['local_unit'] = charmhelpers.core.hookenv.local_unit()
 
-
     # Don't use non-standard tags for unicode which will not
     # work when salt uses yaml.load_safe.
     yaml.add_representer(unicode, lambda dumper,

=== modified file 'charmhelpers/fetch/__init__.py'
--- charmhelpers/fetch/__init__.py	2014-01-17 15:06:04 +0000
+++ charmhelpers/fetch/__init__.py	2014-03-03 12:31:59 +0000
@@ -135,6 +135,10 @@
 
 
 def add_source(source, key=None):
+    if source is None:
+        log('Source is not present. Skipping')
+        return
+
     if (source.startswith('ppa:') or
         source.startswith('http') or
         source.startswith('deb ') or