In FullDB mode, if a GO artifact with a 'zip' extension is requested from a remote in Artifactory, if the artifact exists in the remote repository-cache but not in the file-system cache-fs there is a possible connection leak

Tested with Artifactory version 6.12.2 and FullDB mode.

When a GO artifact with a ‘zip’ extension is requested from Artifactory and the artifact in itself exists in the remote GO repository-cache in Artifactory but not exists in the file-system cache a connection will open and will not get closed.

Steps to reproduce:

1. Install Artifactory with FullDB mode
2. Configure cache-fs
3. Create a GO virtual repository which aggregate a GO remote repository.
4. issue a curl command to get and cache an artifact with a 'zip' extension
5. delete the binary from the cache-fs
6. issue the curl command from #4 again
7. notice an active connection which not getting closed (can be monitored with Jconsole)