The initial structure for vendor and personal branches makes use of the 
default remote (normally origin) for the upstream repository). 
Unfortunately, this causes some confusion, especially for personal 
branches because a push will not push to the correct upstream location. 
This can be 'fixed' by adding a push refspec for the remote, but that 
has the unfortunate consequence of breaking the push.default behaviour 
for git push, and it becomes too easy to accidentally commit something 
unintended to the main parts of the repository.

To work around this, this patch changes the configuration to use 
separate 'remotes' for these additional refs, with one remote for the 
personal space and another remote for each vendor's space.  The personal 
space is called after the user's preferred branch-space prefix (default 
'me'), the vendor spaces are called vendors/<vendor-name>.

As far as possible, I've made the script automatically restructure any 
existing fetch or push lines that earlier versions of the scripts may 
have created - the gcc-git-customization.sh script will convert all 
vendor refs that it can find, so it is not necessary to re-add any 
vendors you've already added.

You might, however, want to run
   git remote prune <origin>
after running to clean up any stale upstream-refs that might still be in 
your local repo, and then
   git fetch vendors/<vendor>
or
   git fetch <me>
to re-populate the remotes/ structures.

Also, for any branch you already have that tracks a personal or vendor 
branch upstream, you might need to run
   git config branch.<name>.remote <new-remote>

so that merges and pushes go to the right place (I haven't attempted to 
automate this last part).

For vendors, the new structure means that

   git checkout -b <vendor>/<branch> remotes/vendors/<vendor>/<branch>

will correctly set up a remote tracking branch.

Please be aware that if you have multiple personal branches set up, then

   git push <me>

will still consider all of them for pushing.  If you only want to push 
one branch, then either write
   git push <me> HEAD
or
   git push <me> <me>/branch
as appropriate.

And don't forget '-n' (--dry-run) to see what would be done if this were 
not a dry run.

Finally, now that the vendors spaces are isolated from each other and 
from the other spaces, I've added an option "--enable-push" to 
git-fetch-vendor.sh.  If passed, then a "push" spec will be added for 
that vendor to enable pushing to the upstream.  If you re-run the script 
for the same vendor without the option, the push spec will be removed.

	* gcc-git-customization.sh: New personal and vendor layout.
	Convert any existing fetch/push rules to new layout.
	* git-fetch-vendor.sh: New vendor layout.  Add --enable-push
	option.