Summary: Fix S3 from trying to upload directories found in template dirs

Detail: The S3 upload code fails on directories in the templates dir, such as
"KVMHA" that gets created for KVM. This skips directories in the templates dir.

BUG-ID: CLOUDSTACK-1056
Bugfix-for: 4.1 (master)
Signed-off-by: Marcus Sorensen <marcus@betterservers.com> 1359390176 -0700