[WebSocket] Prevent division by 0 in Hixie handshake

src/Ratchet/WebSocket/Version/Hixie76.php

@@ -103,6 +103,10 @@ class Hixie76 implements VersionInterface {
     }
 
     public function generateKeyNumber($key) {
+        if (0 === substr_count($key, ' ')) {
+            return 0;
+        }
+
         return preg_replace('[\D]', '', $key) / substr_count($key, ' ');
     }
 

tests/Ratchet/Tests/WebSocket/Version/Hixie76Test.php

@@ -32,6 +32,7 @@ class Hixie76Test extends \PHPUnit_Framework_TestCase {
         return array(
             array(179922739, '17  9 G`ZD9   2 2b 7X 3 /r90')
           , array(906585445, '3e6b263  4 17 80')
+          , array(0, '3e6b26341780')
         );
     }