Check iface by TextUtils.equals

In current equals method, if iface is null then it will cause
null object reference when checking iface.
Thus, use TextUtils.equals to check iface so that it can compare
null iface.

Bug: 210073043
Test: FrameworksNetTests, NetworkStaticLibTests
Change-Id: I2bd8127cb030ea54438382ee89961590fffbc31a
1 file changed