Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/Protobuf.podspec

Index: third_party/protobuf/Protobuf.podspec
diff --git a/third_party/protobuf/Protobuf.podspec b/third_party/protobuf/Protobuf.podspec
index 92ff290437e6dcb4d787e7def4b1c34a9b35d148..0bbd06df0172b87e6cde9dd646ef9149d86934de 100644
--- a/third_party/protobuf/Protobuf.podspec
+++ b/third_party/protobuf/Protobuf.podspec
@@ -5,16 +5,18 @@
 # dependent projects use the :git notation to refer to the library.
 Pod::Spec.new do |s|
   s.name     = 'Protobuf'
-  s.version  = '3.0.0-alpha-4.1'
+  s.version  = '3.0.0-beta-2'
   s.summary  = 'Protocol Buffers v.3 runtime library for Objective-C.'
   s.homepage = 'https://github.com/google/protobuf'
   s.license  = 'New BSD'
   s.authors  = { 'The Protocol Buffers contributors' => 'protobuf@googlegroups.com' }
 
+  s.source = { :git => 'https://github.com/google/protobuf.git',
+               :tag => "v#{s.version}" }
+
   s.source_files = 'objectivec/*.{h,m}',
                    'objectivec/google/protobuf/Any.pbobjc.{h,m}',
                    'objectivec/google/protobuf/Api.pbobjc.{h,m}',
-                   'objectivec/google/protobuf/Descriptor.pbobjc.{h,m}',
                    'objectivec/google/protobuf/Duration.pbobjc.h',
                    'objectivec/google/protobuf/Empty.pbobjc.{h,m}',
                    'objectivec/google/protobuf/FieldMask.pbobjc.{h,m}',