Handle authentication failures when accessing /api/info/.

When accessing a password-protected /api/info/ path, we wouldn't gracefully
handle an invalid login. Instead, we would fall back on the old, deprecated
API. This would always fail on RB 1.6, making things very confusing. Now we
handle this better and just simply bail if we can't log in the first time.

rbtools/postreview.py

@@ -516,7 +516,7 @@ def check_api_version(self):
                 self.deprecated_api = False
                 self.root_resource = root_resource
                 debug('Using the new web API')
-                return
+                return True
         except APIError, e:
             if e.http_status not in (401, 404):
                 # We shouldn't reach this. If there's a permission denied
@@ -528,9 +528,12 @@ def check_api_version(self):
                 # done your http basic auth
                 die("Unable to access the root /api/ URL on the server.")
 
+            return False
+
         # This is an older Review Board server with the old API.
         self.deprecated_api = True
         debug('Using the deprecated Review Board 1.0 web API')
+        return True
 
     def login(self, force=False):
         """
@@ -3949,7 +3952,10 @@ def main():
         sys.exit(1)
 
     server = ReviewBoardServer(server_url, repository_info, cookie_file)
-    server.check_api_version()
+
+    # Handle the case where /api/ requires authorization (RBCommons).
+    if not server.check_api_version():
+        die("Unable to log in with the supplied username and password.")
 
     if repository_info.supports_changesets:
         changenum = tool.get_changenum(args)