GUI - 1264, 1265 When creating a new security group, if the VPC option is changed, remove...

... the previoisly added rules since now the security groups are specific to VPCs

https://eucalyptus.atlassian.net/browse/GUI-1264
https://eucalyptus.atlassian.net/browse/GUI-1265

The fucntion clearRules() calls the function syncRules(), which in turn, calls the function resetValues(), thus this line would be redundant, therefore removed.