Use source relative paths for generated proto bindings

After 16cb78fd, protobuf GN template generates bindings using source
relative paths. Update their usage accordingly.

Change-Id: I42a7625a9e7ad26399af8019a95359873ab3f2df
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/luci-go/+/403997
Reviewed-by: Shai Barack <shayba@google.com>
diff --git a/resultdb/proto/v1/BUILD.gn b/resultdb/proto/v1/BUILD.gn
index f9bfb19..dad15ed 100644
--- a/resultdb/proto/v1/BUILD.gn
+++ b/resultdb/proto/v1/BUILD.gn
@@ -25,7 +25,7 @@
 
 go_library("resultdb_proto_go") {
   name = "go.chromium.org/luci/resultdb/proto/v1"
-  source_dir = "$root_gen_dir/go-proto-gen/src/third_party/luci-go/resultdb/proto/v1/go.chromium.org/luci/resultdb/proto/v1/"
+  source_dir = "$root_gen_dir/go-proto-gen/src/third_party/luci-go/resultdb/proto/v1"
   non_go_deps = [ ":resultdb_proto" ]
   sources = []
 
@@ -33,4 +33,4 @@
     sources += [ "${name}.pb.go" ]
   }
   deps = [ "//third_party/golibs:github.com/golang/protobuf" ]
-}
\ No newline at end of file
+}
diff --git a/resultdb/sink/proto/v1/BUILD.gn b/resultdb/sink/proto/v1/BUILD.gn
index 393e6cc..ae57bca 100644
--- a/resultdb/sink/proto/v1/BUILD.gn
+++ b/resultdb/sink/proto/v1/BUILD.gn
@@ -27,7 +27,7 @@
 
 go_library("resultsink_proto_go") {
   name = "go.chromium.org/luci/resultdb/sink/proto/v1"
-  source_dir = "$root_gen_dir/go-proto-gen/src/third_party/luci-go/resultdb/sink/proto/v1/go.chromium.org/luci/resultdb/sink/proto/v1/"
+  source_dir = "$root_gen_dir/go-proto-gen/src/third_party/luci-go/resultdb/sink/proto/v1"
   non_go_deps = [ ":resultsink_proto" ]
   sources = []