Cobbler docker mode fixes

Skip cobbler::iptables in docker container for
all docker modes and don't create profiles and
distros during docker build.

IPtables cannot be modified inside a Docker
container. It creates errors that interfere
with deployment.

Change-Id: I9c3f54f3c0fd2afdcb425d37a3daecfa3c0173af
Closes-Bug: #1342075
Related-Bug: #1337288
Merge "Cobbler docker mode fixes"