Update Atmosphere vaadin2 patch (#12181)

pom.xml

@@ -35,7 +35,7 @@
         <javax.portlet.version>2.0</javax.portlet.version>
         <vaadin.sass.version>0.9.13</vaadin.sass.version>
         <!-- Note that this should be kept in sync with the class Constants -->
-        <atmosphere.runtime.version>2.4.30.vaadin1</atmosphere.runtime.version>
+        <atmosphere.runtime.version>2.4.30.vaadin2</atmosphere.runtime.version>
 
         <!-- OSGi -->
         <osgi.execution.environment>JavaSE-1.8</osgi.execution.environment>

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

@@ -66,7 +66,7 @@ public interface Constants {
             + "=================================================================";
 
     // Keep the version number in sync with pom.xml
-    static final String REQUIRED_ATMOSPHERE_RUNTIME_VERSION = "2.4.30.vaadin1";
+    static final String REQUIRED_ATMOSPHERE_RUNTIME_VERSION = "2.4.30.vaadin2";
 
     static final String INVALID_ATMOSPHERE_VERSION_WARNING = "\n"
             + "=================================================================\n"