buildifier formatting of bazel files

Change-Id: I8196aa52ee640d1c500307a50a0ab4921138b69b
diff --git a/tools/build/bazel/variables.bzl b/tools/build/bazel/variables.bzl
index a164970..7c32f8a 100644
--- a/tools/build/bazel/variables.bzl
+++ b/tools/build/bazel/variables.bzl
@@ -1,6 +1,6 @@
-ONOS_ORIGIN = 'ONOS Community'
-ONOS_GROUP_ID = 'org.onosproject'
-ONOS_VERSION = '1.14.0-SNAPSHOT'
-DEFAULT_APP_CATEGORY = 'Utility'
-ONOS_ARTIFACT_BASE = 'onos-'
-APP_PREFIX = ONOS_GROUP_ID + '.'
\ No newline at end of file
+ONOS_ORIGIN = "ONOS Community"
+ONOS_GROUP_ID = "org.onosproject"
+ONOS_VERSION = "1.14.0-SNAPSHOT"
+DEFAULT_APP_CATEGORY = "Utility"
+ONOS_ARTIFACT_BASE = "onos-"
+APP_PREFIX = ONOS_GROUP_ID + "."