Print error when netlink socket not created.
Print error when netlink socket not created.

The panic here didn't show what error might be encountered
(EPERM, for instance).

Bug: 228077254
Test: check log on error
Change-Id: I56f34f87430a68266af85ba1d0abb2aeb2c05407
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3569267
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Andrew Walbran <91a7c1b7f9f624e0ed1b099dc85ecb6025941ee9@google.com>
Commit-Queue: Steven Moreland <4840f2e2fca2d2af23b5ddcdd6ec59bfb2c968b2@google.com>

google/crosvm,google/crosvm,google/crosvm,google/crosvm