Clarify that the CC-BY 3.0 license is the unported version

The text in the license file is from the unported version, so rename
it and update the link.

Since the Silk Icons license now explicitly includes the license text,
we don't need the dependency any more.  Remove it.

Change-Id: I014ffbf24ee424ecf5422f2704fac66e6b7a6a36

gerrit-gwtui-common/BUCK

@@ -41,7 +41,7 @@ prebuilt_jar(
   binary_jar = ':diffy_image_files_ln',
   deps = [
     '//lib:LICENSE-diffy',
-    '//lib:LICENSE-CC-BY3.0',
+    '//lib:LICENSE-CC-BY3.0-unported',
   ],
   visibility = ['PUBLIC'],
 )

gerrit-gwtui/BUCK

@@ -47,7 +47,6 @@ java_library(
   name = 'silk_icons',
   deps = [
     '//lib:LICENSE-silk_icons',
-    '//lib:LICENSE-CC-BY3.0',
   ],
 )
 

lib/LICENSE-CC-BY3.0-unported

@@ -1,4 +1,4 @@
-link:http://creativecommons.org/licenses/by/3.0/us/[CC-BY 3.0]
+link:http://creativecommons.org/licenses/by/3.0/[CC-BY 3.0]
 
 THE WORK (AS DEFINED BELOW) IS PROVIDED UNDER THE TERMS OF THIS
 CREATIVE COMMONS PUBLIC LICENSE ("CCPL" OR "LICENSE").  THE WORK IS