Update Travis CI matrix to include PHP 7.2.0alpha3

Author: sodabrew

Diff for: .travis.yml

@@ -3,7 +3,7 @@ dist: trusty
 
 language: php
 php:
-    - 7.2.0alpha2
+    - 7.2.0alpha3
     - 7.1
     - 7.0
 

Diff for: tests/session_badconf_servers.phpt

@@ -24,5 +24,9 @@ ini_set('session.save_path', '');
 session_start();
 session_write_close();
 
---EXPECTF--
-session_start(): failed to parse session.save_path
+
+// The second error appears in PHP 7.2, use EXPECTREGEX for an all-or-nothing match
+
+--EXPECTREGEX--
+session_start\(\): failed to parse session.save_path
+(session_start\(\): Failed to initialize storage module: memcached \(path: \))?