Bazel: add filegroups for better query support

Summary: This ensures `bazel query kythe/release/kythe.sh` works even without `kythe.sh` being used in a target.

Reviewers: zarko

Reviewed By: zarko

Differential Revision: https://phabricator-dot-kythe-repo.appspot.com/D209

BUILD

@@ -0,0 +1,3 @@
+package(default_visibility = ["//visibility:private"])
+
+exports_files(glob(["*"]))

buildtools/linter.sh

@@ -33,7 +33,7 @@ lint_campfire() {
 
 lint_copyright() {
   case $file in
-    third_party/*|*.md|CAMPFIRE|*/BUILD|.campfire_settings|buildtools/*|*/testdata/*|*.yaml|*.json|*.html|*.pb.go|.arclint|.gitignore|*.bzl)
+    third_party/*|*.md|CAMPFIRE|BUILD|*/BUILD|.campfire_settings|buildtools/*|*/testdata/*|*.yaml|*.json|*.html|*.pb.go|.arclint|.gitignore|*.bzl)
       ;; # skip copyright checks
     *)
       if ! grep -Pq 'Copyright 201[45] Google Inc. All rights reserved.' "$file"; then

kythe/BUILD

@@ -6,3 +6,9 @@ package_group(
         "//kythe/...",
     ],
 )
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+    visibility = ["//visibility:private"],
+)

third_party/BUILD

@@ -1,5 +1,11 @@
 package(default_visibility = ["//visibility:public"])
 
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+    visibility = ["//visibility:private"],
+)
+
 java_import(
     name = "junit4",
     jars = [