Update to Atmosphere 2.2.9.vaadin2 (#19742)

Change-Id: I634e44971c6e4f653ecdcbf694be78ae67ef728f

pom.xml

@@ -41,7 +41,8 @@
 		<junit.version>4.11</junit.version>
 
 		<!-- Atmosphere versions -->
-		<atmosphere.runtime.version>2.2.7.vaadin1</atmosphere.runtime.version>
+		<!-- Note that this should be kept in sync with the class Constants -->
+		<atmosphere.runtime.version>2.2.9.vaadin2</atmosphere.runtime.version>
 		<atmosphere.js.version>2.2.6.vaadin4</atmosphere.js.version>
 
 		<!-- Dependency unpack directory -->

server/src/main/java/com/vaadin/server/Constants.java

@@ -66,9 +66,8 @@ public interface Constants {
             + " Widgetset version: %s\n"
             + "=================================================================";
 
-    // Keep the version number in sync with push/build.xml and other locations
-    // listed in that file
-    static final String REQUIRED_ATMOSPHERE_RUNTIME_VERSION = "2.2.7.vaadin1";
+    // Keep the version number in sync with pom.xml
+    static final String REQUIRED_ATMOSPHERE_RUNTIME_VERSION = "2.2.9.vaadin2";
 
     static final String INVALID_ATMOSPHERE_VERSION_WARNING = "\n"
             + "=================================================================\n"