Relieve ios deployment version to 7.0
diff --git a/gRPC-ProtoRPC.podspec b/gRPC-ProtoRPC.podspec
index 8fbdf7a..e464403 100644
--- a/gRPC-ProtoRPC.podspec
+++ b/gRPC-ProtoRPC.podspec
@@ -48,7 +48,7 @@
     :tag => "v#{version}",
   }
 
-  s.ios.deployment_target = '7.1'
+  s.ios.deployment_target = '7.0'
   s.osx.deployment_target = '10.9'
 
   name = 'ProtoRPC'