Guard against null component when binding KeyChain

If keychain is removed from a device, there will be no sensible
resolution and client apps will bind to whatever is available.

Doesn't affect system apps which are forcibly prevented from wildcard
binding.

Bug: 27475655
Change-Id: Ide1aab3778e12f0b9a96662deb297a76d2f4997f
1 file changed