Add waiting for mongo in travis build

Author: Jonathan Gaillard

.travis.yml

@@ -18,4 +18,6 @@ before_install:
 before_script:
   - composer self-update
   - yes '' | pecl install -f mongo-${EXT_VERSION}
+    # wait for mongo, start is only needed for 2.4 package, see http://tldp.org/LDP/abs/html/devref1.html for description of this syntax.
+  - sudo service mongodb start; bash -c 'while ! exec 6<>/dev/tcp/localhost/27017; do echo "$(date) - still trying to connect to mongo"; sleep 1; done'
 script: ./build.php