Replace repo links.

csharp/protos/unittest_issues.proto

diff --git a/csharp/protos/unittest_issues.proto b/csharp/protos/unittest_issues.proto
index 0d8793e..1619f13 100644
--- a/csharp/protos/unittest_issues.proto
+++ b/csharp/protos/unittest_issues.proto
@@ -18,7 +18,7 @@
 }
 
 // Old issue 13: http://code.google.com/p/protobuf-csharp-port/issues/detail?id=13
-// New issue 309: https://github.com/google/protobuf/issues/309
+// New issue 309: https://github.com/protocolbuffers/protobuf/issues/309
  
 // message A {
 //    optional int32 _A = 1;
@@ -34,7 +34,7 @@
 
 // Similar issue with numeric names
 // Java code failed too, so probably best for this to be a restriction.
-// See https://github.com/google/protobuf/issues/308
+// See https://github.com/protocolbuffers/protobuf/issues/308
 // message NumberField {
 //    optional int32 _01 = 1;
 // }