Allow per-user override of -R setting.

Introduce "gitreview.rebase" user configuration
option.

Change-Id: I96dfab1af48d8f1592766fea4b97e0f35c03d8a5

git-review

@@ -917,6 +917,11 @@ def finish_branch(target_branch):
     print("Deleted branch '%s'" % local_branch)
 
 
+def convert_bool(one_or_zero):
+    "Return a bool on a one or zero string."
+    return one_or_zero in ["1", "true", "True"]
+
+
 def print_exit_message(status, needs_update):
 
     if needs_update:
@@ -939,6 +944,10 @@ def main():
     config = get_config(os.path.join(top_dir, ".gitreview"))
     hook_file = os.path.join(git_dir, "hooks", "commit-msg")
 
+    defaultrebase = convert_bool(
+        git_config_get_value("gitreview", "rebase",
+                             default=str(config['defaultrebase'])))
+
     usage = "git review [OPTIONS] ... [BRANCH]"
 
     import argparse
@@ -1037,7 +1046,7 @@ def main():
     parser.add_argument("branch", nargs="?", default=config['defaultbranch'])
     parser.set_defaults(dry=False,
                         draft=False,
-                        rebase=config['defaultrebase'],
+                        rebase=defaultrebase,
                         verbose=False,
                         update=False,
                         setup=False,

git-review.1

@@ -179,6 +179,27 @@ file:
 [gitreview]
 username=\fImygerrituser\fP
 .Ed
+.It gireview.rebase
+This setting determines whether changes submitted will
+be rebased to the newest state of the branch.
+.Pp
+A value of 'true' or 'false' should be specified.
+.Bl -tag
+.It false
+Do not rebase changes on submit - equivalent to setting
+.Fl R
+when submitting changes.
+.It true
+Do rebase changes on submit. This is the default value unless
+overridden by
+.Pa .gitreview
+file.
+.El
+.Pp
+This setting takes precedence over repository-specific configuration
+in the
+.Pa .gitreview
+file.
 .El
 .Sh FILES
 To use