Backport (7.8) - Regression - Channel manager blue print, event subsite: Document Folder is created for an incorrect channel configuration

1. Log in to CMS as admin
2. Navigate to channel manager >> add channel >> select Event susbite
3. Define name & in url put the following "http://localhost/site/qatwosubsite"

Expected - Warning is shown, no channel or folder or documents are created.
Actual - Warning is shown & channel is not created but Folder & documents for this incorrect subsite is created (refer screenshot)

Below info message is shown in terminal -
[INFO] [talledLocalContainer] 12.08.2013 15:38:28 WARN [org.hippoecm.hst.cmsrest.services.ChannelsResource.persist():103] Error while persisting a new channel - Channel: Channel

{id=null,name=QA three subsite,type=website,url=http://localhost/site/qathreesusbite,hstConfigPath=/hst:hst/hst:configurations/qa-three-subsite,contentRoot=null,locale=null,contextPath=null,cmsPreviewPrefix=null,mountPath=null,lockedBy=null,lockedOn=null,devices=[desktop, ipad_landscape, ipad_portrait],defaultDevice=default}

- org.hippoecm.hst.configuration.channel.ChannelException : org.hippoecm.hst.configuration.channel.ChannelException: Mount not found: /hst:hst/hst:hosts/dev-localhost/localhost/hst:root/site