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

third_party/protobuf/csharp/generate_protos.sh

 #!/bin/bash
 # Generates C# source files from .proto files.
 # You first need to make sure protoc has been built (see instructions on
 # building protoc in root of this repository)
 
-# This script performs a few fix-ups as part of generation. These are:
-# - descriptor.proto is renamed to descriptor_proto_file.proto before
-#   generation, to avoid the naming collision between the class for the file
-#   descriptor and its Descriptor property
-# - This change also impacts UnittestCustomOptions, which expects to
-#   use a class of Descriptor when it's actually been renamed to
-#   DescriptorProtoFile.
-# - Issue 307 (codegen for double-nested types) breaks Unittest.proto and
-#   its lite equivalents.
-
 set -ex
 
 # cd to repository root
-cd $(dirname $0)/..
+pushd $(dirname $0)/..
 
 # Protocol buffer compiler to use. If the PROTOC variable is set,
 # use that. Otherwise, probe for expected locations under both
 # Windows and Unix.
 if [ -z "$PROTOC" ]; then
   # TODO(jonskeet): Use an array and a for loop instead?
   if [ -x cmake/build/Debug/protoc.exe ]; then
     PROTOC=cmake/build/Debug/protoc.exe
   elif [ -x cmake/build/Release/protoc.exe ]; then
     PROTOC=cmake/build/Release/protoc.exe
@@ skipping 31 matching lines @@
 
 # Different base namespace to the protos above
 $PROTOC -Icsharp/protos --csharp_out=csharp/src/Google.Protobuf.Test \
     --csharp_opt=base_namespace=UnitTest.Issues \
     csharp/protos/unittest_issues.proto
 
 # AddressBook sample protos
 $PROTOC -Iexamples --csharp_out=csharp/src/AddressBook \
     examples/addressbook.proto
 
-$PROTOC -Iconformance --csharp_out=csharp/src/Google.Protobuf.Conformance \
+$PROTOC -Iconformance -Isrc --csharp_out=csharp/src/Google.Protobuf.Conformance \
     conformance/conformance.proto