upgrading from from-client method to non-root method

Since the from-client method is now deprecated for reasons explained elsewhere, some folks may want to do their next upgrade using the non-root method.

There are many, many ways to skin this cat; here's one way:

follow non-root install but stop after the gl-system-install step
temporarily rename your ~/.gitolite.rc file to something else
now run the gl-setup step

(background: this will create a default rc file with default values, but crucially, it will give you the correct values for two very critical variables that are not used in the old from-client install method)
edit ~/.gitolite.rc and bring in any non-default settings you may have had in your old rc file.

When you're done, the only difference between your old and current rc files should be that the $GL_PACKAGE_CONF and the $GL_PACKAGE_HOOKS variables are no longer commented out and look somewhat like this:
```
$GL_PACKAGE_CONF = '/home/git/share/gitolite/conf';
$GL_PACKAGE_HOOKS = '/home/git/share/gitolite/hooks';
```
Now save the file.