Prefer the term "3-Clause BSD License" over "New BSD License"

The first is the newer name, which is also more telling.
diff --git a/Protobuf.podspec b/Protobuf.podspec
index 4b88a4d..0db7065 100644
--- a/Protobuf.podspec
+++ b/Protobuf.podspec
@@ -8,7 +8,7 @@
   s.version  = '3.2.0'
   s.summary  = 'Protocol Buffers v.3 runtime library for Objective-C.'
   s.homepage = 'https://github.com/google/protobuf'
-  s.license  = 'New BSD'
+  s.license  = '3-Clause BSD License'
   s.authors  = { 'The Protocol Buffers contributors' => 'protobuf@googlegroups.com' }
   s.cocoapods_version = '>= 1.0'