Attempt to fix apcu install issues.

.travis.yml

@@ -43,7 +43,7 @@ before_script:
   - sh -c "if [ '$PHPCS' = '1' ]; then composer global require 'cakephp/cakephp-codesniffer:1.*'; fi"
   - sh -c "if [ '$PHPCS' = '1' ]; then ~/.composer/vendor/bin/phpcs --config-set installed_paths ~/.composer/vendor/cakephp/cakephp-codesniffer; fi"
   - echo "extension = memcached.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-  - if [[ ${TRAVIS_PHP_VERSION:0:3} == "7.0" ]] ; then print "yes" | pecl install apcu-5.1.3; else print "yes" | pecl install apcu-4.0.11; fi
+  - if [[ ! $(php -m) =~ 'apcu' ]] ; then print "yes" | pecl install apcu; fi
   - echo -e "extension = apcu.so\napc.enable_cli=1" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
   - phpenv rehash
   - set +H