Fixed php 7.3 compatibility for elasticsearch 6 (#827)

.travis.yml

@@ -30,6 +30,9 @@ matrix:
     - php: 7.2
       env: ES_VERSION="6.0"
 
+    - php: 7.3
+      env: ES_VERSION="6.0"
+
   allow_failures:
     - env: ES_VERSION="6.x"
 
@@ -43,18 +46,18 @@ before_install:
   - ./travis/download_and_run_es.sh
 
 install:
-  - composer install --prefer-source
+  - composer install --prefer-dist
 
 before_script:
-  - if [ $TRAVIS_PHP_VERSION = '7.0' ]; then PHPUNIT_FLAGS="--coverage-clover ./build/logs/clover.xml"; fi
+  - if [ $TRAVIS_PHP_VERSION = '7.3' ]; then PHPUNIT_FLAGS="--coverage-clover ./build/logs/clover.xml"; fi
   - php util/RestSpecRunner.php
   - php util/EnsureClusterAlive.php
 
 script:
-  - composer run-script phpcs
+  - if [ $TRAVIS_PHP_VERSION != '7.3' ]; then composer run-script phpcs; fi
   - composer run-script phpstan
   - vendor/bin/phpunit $PHPUNIT_FLAGS
   - vendor/bin/phpunit -c phpunit-integration.xml --group sync $PHPUNIT_FLAGS
 
 after_script:
-  - if [ $TRAVIS_PHP_VERSION = '7.0' ]; then php vendor/bin/coveralls; fi
+  - if [ $TRAVIS_PHP_VERSION = '7.3' ]; then php vendor/bin/coveralls; fi

src/Elasticsearch/ClientBuilder.php

@@ -683,7 +683,7 @@ private function extractURIParts($host)
      */
     private function prependMissingScheme($host)
     {
-        if (!filter_var($host, FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED)) {
+        if (!filter_var($host, FILTER_VALIDATE_URL)) {
             $host = 'http://' . $host;
         }