Drop workaround for Python < 3.10

... because 3.10 is the current minimum version.

Change-Id: I346219086b27410fc95613f12ed9790bd281c347
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

manilaclient/tests/functional/test_common.py

@@ -34,11 +34,7 @@ class ManilaClientTestCommonReadOnly(base.BaseTestCase):
 
         commands = []
         cmds_start = lines.index('Positional arguments:')
-        try:
-            # TODO(gouthamr): Drop when py3.10 becomes min supported version
-            cmds_end = lines.index('Optional arguments:')
-        except ValueError:
-            cmds_end = lines.index('Options:')
+        cmds_end = lines.index('Options:')
         command_pattern = re.compile(r'^ {4}([a-z0-9\-\_]+)')
         for line in lines[cmds_start:cmds_end]:
             match = command_pattern.match(line)