ZP-878 Set IpcSharedMemoryProvider as default IPC_PROVIDER in develop.

Released under the Affero GNU General Public License (AGPL) version 3.

src/config.php

@@ -83,7 +83,7 @@
  *  When another implementation should be used, the class can be set here explicitly.
  *  If empty Z-Push will try to use available providers.
  */
-    define('IPC_PROVIDER', '');
+    define('IPC_PROVIDER', 'IpcSharedMemoryProvider');
 
 /**********************************************************************************
  *  Logging settings