Skip boto 2.x tests if boto is not installed

The boto library was last updated two years ago and has
rusted to the point that it's unusable on py312 -- see
https://github.com/boto/boto/issues/3951

We should transition all of these tests to boto3 equivalents,
but this should help out in the meantime.

Related-Bug: #1557260
Related-Bug: #2063367
Change-Id: If95f45371f352c6a2d16be1a3e1b64e265bccfb4

test/functional/s3api/__init__.py

@@ -24,6 +24,10 @@ import os
 import test.functional as tf
 from test.functional.s3api.s3_test_client import (
     Connection, get_boto3_conn, tear_down_s3)
+try:
+    import boto
+except ImportError:
+    boto = None
 
 
 def setUpModule():
@@ -52,6 +56,8 @@ class S3ApiBase(unittest.TestCase):
             raise SkipTest('no s3api user configured')
         if 's3api' not in tf.cluster_info:
             raise SkipTest('s3api middleware is not enabled')
+        if boto is None:
+            raise SkipTest('boto 2.x library is not installed')
         if tf.config.get('account'):
             user_id = '%s:%s' % (tf.config['account'], tf.config['username'])
         else:

test/functional/s3api/s3_test_client.py

@@ -19,8 +19,14 @@ from six.moves.urllib.parse import urlparse
 import test.functional as tf
 import boto3
 from botocore.exceptions import ClientError
-from boto.s3.connection import S3Connection, OrdinaryCallingFormat, \
-    S3ResponseError
+try:
+    from boto.s3.connection import (
+        S3Connection,
+        OrdinaryCallingFormat,
+        S3ResponseError,
+    )
+except ImportError:
+    S3Connection = OrdinaryCallingFormat = S3ResponseError = None
 import six
 import sys
 import traceback