Make sure php-fpm logging will work on piwik-ui-tests.

UI @ db7c320e

-Subproject commit 0d1ba533c9a6fcde695ae97b95c65a0665638946
+Subproject commit db7c320e79a3fc03ad05ab0e13d43d01a831bdf1

tests/travis/setup_webserver.sh

@@ -14,7 +14,7 @@ echo "Configuring php-fpm"
 PHP_FPM_BIN="$HOME/.phpenv/versions/$TRAVIS_PHP_VERSION/sbin/php-fpm"
 PHP_FPM_CONF="$DIR/php-fpm.conf"
 PHP_FPM_SOCK=$(realpath "$DIR")/php-fpm.sock
-PHP_FPM_LOG="$TRAVIS_BUILD_DIR/tmp/php-fpm.log"
+PHP_FPM_LOG="$TRAVIS_BUILD_DIR/../piwik/tmp/php-fpm.log"
 
 USER=$(whoami)