Avoid use of uninitialized memory in GrVkCaps.cpp

This came up on an internal scan
http://sponge2/c6a35152-1d6a-498a-9365-0960c007a491

properties appears to have been read even if the call failed.

Change-Id: I1730453537f9634d93ee83df193c2a9c4785564e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1156556
Commit-Queue: Kaylee Lubick <kjlubick@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>