shill: wifi: Remove unused constant.

BUG=None
TEST=`USE='clang asan' FEATURES=test emerge-$BOARD platform2`

Change-Id: I84878b3f7dce91f0c39ba668cbc5870f3201cc18
Reviewed-on: https://chromium-review.googlesource.com/212717
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
diff --git a/wake_on_wifi_unittest.cc b/wake_on_wifi_unittest.cc
index 5e5c090..c1f043f 100644
--- a/wake_on_wifi_unittest.cc
+++ b/wake_on_wifi_unittest.cc
@@ -31,7 +31,6 @@
 static const uint8_t kIPV4MaskBytes[] = {0x00, 0x00, 0x00, 0x3c};
 static const uint8_t kIPV6MaskBytes[] = {0x00, 0x00, 0xc0, 0xff, 0x3f};
 
-static const char kEmptyIPAddress[] = "";
 static const char kIPV4Address0[] = "192.168.10.20";
 static const uint8_t kIPV4Address0Bytes[] = {0xc0, 0xa8, 0x0a, 0x14};
 static const char kIPV4Address1[] = "1.2.3.4";