Clean up: Remove a few redundant 'scm' properties

* scm 'git-remote-zuul-no-submodules' for a job with
  default 'use-remote-zuul-no-submodules' (that scm is already
  specified in defaults.yaml for that default).

* scm 'git-remote-zuul' for a job with
  default 'use-remote-zuul' (that scm is already
  specified in defaults.yaml for that default).

Verified for a few random jobs that the output is 100% equal.

Change-Id: I861daa6ef284a4b228a9d3ad99e635f31aa0d25e