git-review gets its configuration from multiple sources (by priority):
* command line options
* git-config
* options: username, rebase
* with local/global/system config
* git-review config files
* options: scheme, host, port, project, defaultbranch/remote/rebase
* locally using .gitreview
* globally using ~/.config/gitreview/git-review.conf
* system using /etc/git-review/git-review.conf
.gitreview file is commonly provided versioned in the git repo, where
other git-review config files and git-config is done by developers. It
implies for developers multiple places to define local/global/system
configuration options but some can only be changed by updating
.gitreview (scheme/port...) which is under versioning.
This change proposes to use as configuration sources (by priority):
* command line options
* git-config for developer local/global/system config
* options: username, rebase and all .gitreview options
* .gitreview local file for repo provided specific config
and deprecates git-review global/system files in order to reduce
configuration sources and allow to overload .gitreview configuration
without updating it.
Change-Id: I24aba0fa089de57d51a79049d9c192f76d576f69
1bc87f26d6