Dont install memcached for PHP 5.6 too.

Tests seem to fail for no reason.

.travis.yml

@@ -59,7 +59,10 @@ before_install:
   - if [ $DB = 'pgsql' ]; then psql -c 'CREATE SCHEMA test3;' -U postgres -d cakephp_test; fi
 
   - if [[ $DEFAULT = 1 || $PHPSTAN = 1 ]] ; then pecl channel-update pecl.php.net; fi;
-  - if [[ ${TRAVIS_PHP_VERSION} != "7.3.0RC1" && ($DEFAULT = 1 || $PHPSTAN = 1) ]] ; then echo 'extension = memcached.so' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi
+  - |
+      if [[ ${TRAVIS_PHP_VERSION} != "7.3.0RC1" && ${TRAVIS_PHP_VERSION} != "5.6" && ($DEFAULT = 1 || $PHPSTAN = 1) ]]; then
+        echo 'extension = memcached.so' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini;
+      fi
   - if [[ $DEFAULT = 1 || $PHPSTAN = 1 ]] ; then echo 'extension = redis.so' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi
   - if [[ $DEFAULT = 1 || $PHPSTAN = 1 ]] ; then echo 'extension = apcu.so' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi
   - if [[ $DEFAULT = 1 || $PHPSTAN = 1 ]] ; then echo 'apc.enable_cli = 1' >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi