Fix unit test regex

Previously, the installation source, architecture,
and distribution were all part of a single
component. Now that they are separate, we should
only be checking for the installation source here,
and then later that the distribution is not
unknown.

tests/unit/test_clidriver.py

@@ -776,7 +776,7 @@ def test_user_agent(self, *args):
         machine = platform.machine()
         driver = create_clidriver()
         user_agent_extra_pattern = re.compile(
-            r'^md/installer#source(\.[a-z_]+)?(\.[0-9]+)?$'
+            r'^md/installer#source'
         )
         self.assertIsNotNone(user_agent_extra_pattern.match(
             driver.session.user_agent_extra))