Content repo gc task can delete content in mid-upload

Description of problem:

if upload of an application takes more than 5 minutes, it is removed from repository by clean-obsolete-content.

• start the upload

[Host Controller] 15:44:05,456 INFO [org.jboss.as.repository] (HttpManagementService-threads - 1) JBAS014900: Content added at location /opt/jboss-eap-6.4/domain-dc/data/content/90/828120fc51e4b5f5ededbb5981198b4be93e64/content

• After 5 minutes, the content is removed:

[Host Controller] 15:49:32,111 INFO [org.jboss.as.repository] (Host Controller Service Threads - 33) JBAS014903: Content /opt/jboss-eap-6.4/domain-dc/data/content/90/828120fc51e4b5f5ededbb5981198b4be93e64 is obsolete and will be removed
[Host Controller] 15:49:32,113 INFO [org.jboss.as.repository] (Host Controller Service Threads - 33) JBAS014901: Content removed from location /opt/jboss-eap-6.4/domain-dc/data/content/90/828120fc51e4b5f5ededbb5981198b4be93e64/content

The reference for the deployment is added to domain.xml only after the upload is finished.