Fix deprecated warning with PHP 5.6

When running PHPUnit, we get a lot of PHP Deprecated warnings like this:

Automatically populating $HTTP_RAW_POST_DATA is deprecated [...]

This fixes the issue by setting always_populate_raw_post_data=-1 in
php.ini as recommended.

scripts/travis_before_script.sh

@@ -37,6 +37,22 @@ function step () {
 	echo
 }
 
+# -----------------------------------------------------------------------------
+# Fix deprecated warning in PHP 5.6 builds:
+# "Automatically populating $HTTP_RAW_POST_DATA is deprecated [...]"
+# https://www.bram.us/2014/10/26/php-5-6-automatically-populating-http_raw_post_data-is-deprecated-and-will-be-removed-in-a-future-version/
+# https://bugs.php.net/bug.php?id=66763
+
+if [[ $TRAVIS_PHP_VERSION = '5.6' ]]
+then
+	# Generate custom php.ini settings
+	cat <<-EOF >mantis_config.ini
+		always_populate_raw_post_data=-1
+		EOF
+	phpenv config-add mantis_config.ini
+fi
+
+
 # -----------------------------------------------------------------------------
 step "Create database $MANTIS_DB_NAME"