update-scap-in-beta: Set umask to 0002
Before running git commands on the beta deploy server, set the umask
to 0002 to ensure proper group ownership of files that may be created.
The .git/config of /srv/deployment/scap has
[core]
sharedrepository = 1
but there was a recent case where there were some files/directories
not group-writable, breaking subsequent pulls. This commit attempts
to ensure that doesn't happen.