Make sure the default ec2_group egress rule is not removed

Upon a second run, the default egress rule will be removed when a
vpc is specified but no other egress rules were set. This patch
corrects that behavior by removing the default egress rule from the
list of unmatched outbound rules.

Fixes #7309

library/cloud/ec2_group

@@ -317,7 +317,8 @@ def main():
             # when using a vpc, but no egress rules are specified, 
             # we add in a default allow all out rule, which was the
             # default behavior before egress rules were added
-            if 'out--1-None-None-None-0.0.0.0/0' not in groupRules:
+            default_egress_rule = 'out--1-None-None-None-0.0.0.0/0'
+            if default_egress_rule not in groupRules:
                 ec2.authorize_security_group_egress(
                     group_id=group.id,
                     ip_protocol=-1,
@@ -327,6 +328,9 @@ def main():
                     cidr_ip='0.0.0.0/0'
                 )
                 changed = True
+            else:
+                # make sure the default egress rule is not removed
+                del groupRules[default_egress_rule]
 
         # Finally, remove anything left in the groupRules -- these will be defunct rules
         for rule in groupRules.itervalues():