memcached: replace deprecated calls in test_memcached with approved aliases
memcached: replace deprecated calls in test_memcached with approved aliases

assertEquals should be spelled assertEqual, and assertRegexpMatches should
be spelled assertRegex, according to Python deprecation warnings.  The
approved names are available in Python 3.2, which is sufficiently old.
Message-Id: <97f6cab748c1780cbb9db788ee530dc6fd8024e3@scylladb.com>

dreamsxin/seastar,syuu1228/seastar,syuu1228/seastar,dreamsxin/seastar,dreamsxin/seastar,avikivity/seastar,avikivity/seastar,cloudius-systems/seastar,cloudius-systems/seastar,syuu1228/seastar,scylladb/seastar,avikivity/seastar,scylladb/seastar,cloudius-systems/seastar,scylladb/seastar