wcdo git url switcher

[brettviren]

excerpt from an email

The underlying git actions are the same as for GitHub but the
authentication with Redmine is a little different.

Similar to GitHub, FNAL Redmine has 2 git URLs:

 - https:// "read-only", no push allowed

 - ssh:// "read-write", push allowed

When you use "mrb" to clone some git repo it will first try the second
one and if that fails it will try the first one.  You can later switch
using "git remote set-url origin <newurl>".  In WCT we do this also
using the "switch-git-urls" script.  I should provide a wcdo-* function
to make this easier!

Two example URLs

ssh://[email protected]/cvs/projects/larwirecell
http://cdcvs.fnal.gov/projects/larwirecell

The little script in WCT https://github.com/WireCell/wire-cell-build/blob/master/switch-git-urls