Bump GWT version to 2.6.0

Change-Id: I3353e086112bd1bc4ac9bb2adc35110324c70059
diff --git a/lib/gwt/BUCK b/lib/gwt/BUCK
index b76e580..c855a63 100644
--- a/lib/gwt/BUCK
+++ b/lib/gwt/BUCK
@@ -1,11 +1,11 @@
 include_defs('//lib/maven.defs')
 
-VERSION = '2.6.0-rc3'
+VERSION = '2.6.0'
 
 maven_jar(
   name = 'user',
   id = 'com.google.gwt:gwt-user:' + VERSION,
-  sha1 = 'c9458f276a208add7e3982632bfe1b4058b2e551',
+  sha1 = '8237d1bd37127188107388c8724be44a0e9f73ca',
   license = 'Apache2.0',
   attach_source = False,
 )
@@ -13,7 +13,7 @@
 maven_jar(
   name = 'dev',
   id = 'com.google.gwt:gwt-dev:' + VERSION,
-  sha1 = '01a6e52874ae893949d1046ce2c86d2734a62715',
+  sha1 = 'af3d9ad2fb8be30dc87fdcd6d9a373b2ab675802',
   license = 'Apache2.0',
   deps = [
     ':javax-validation',