Add support for an alternate svn config directory for both svn and git-svn.

Add support for an alternate svn config directory for both svn and git-svn.

Add subversion_config directory.

Otherwise the commit queue messes the user's cached svn credentials. This also
fixes git svn authentication.

BUG=
TEST=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=70086

[M-A Ruel, 2010-12-22 18:17:16]

Dependent on http://codereview.chromium.org/6020010/

This one is quite important since it fixes all the credential cache problems.

[Dirk Pranke, 2010-12-22 23:22:29]

The code looks basically fine, but there are references to an "auth" file and a
"README.txt" that aren't included. Should they be?

Also, I don't understand what using an alternate svn config dir is getting you.
I'm sure it's doing something, but I don't know what, and I don't understand how
it is solving your auth problems. Can you explain in more detail somewhere,
either in the code or in the CL message?

[M-A Ruel, 2010-12-23 04:07:36]

On 2010/12/22 23:22:29, dpranke wrote:
> The code looks basically fine, but there are references to an "auth" file and
a
> "README.txt" that aren't included. Should they be?

Both are generated by the svn client. This is why they are in .gitignore.


> Also, I don't understand what using an alternate svn config dir is getting
you.
> I'm sure it's doing something, but I don't know what, and I don't understand
how
> it is solving your auth problems. Can you explain in more detail somewhere,
> either in the code or in the CL message?

subversion caches the credentials with two ways, at least on linux:
- clear text password in auth subdirectory in its user's config directory
- gnome keyring

I enforce the first method and force the client to use the subversion_config
config directory so if I ever svn up the commit-queue checkout, it will use my
credentials and not the commit-bot@chromium.org credentials.

[M-A Ruel, 2010-12-23 17:32:09]

I'll commit the patch since I use these pending patches to iron out the
remaining issues but feel free to ask me for any follow up changes.