Use latest GAE SDK supporting Java 6

An upgrade of GAE SDK is needed to support the new HDR
that replaced the old DataStore.

Change-Id: I968b01bf4efcf03fae8b3c41d7f0a662f57e7727

server/ivy.xml

@@ -36,7 +36,7 @@
 
         <!-- Google App Engine -->
         <dependency org="com.google.appengine" name="appengine-api-1.0-sdk"
-            rev="1.2.1" conf="build-provided,ide,test -> default" />
+            rev="1.7.7" conf="build-provided,ide,test -> default" />
 
         <!-- Bean Validation API -->
         <dependency org="javax.validation" name="validation-api"

uitest/ivy.xml

@@ -31,7 +31,7 @@
             rev="4.2.0.Final" conf="build,ide -> default" />
         <!-- Google App Engine -->
         <dependency org="com.google.appengine" name="appengine-api-1.0-sdk"
-            rev="1.2.1" conf="build-provided,ide -> default" />
+            rev="1.7.7" conf="build-provided,ide -> default" />
 
         <!-- LIBRARY DEPENDENCIES (compile time) -->
         <!-- Project modules -->