nl80211: fix error path in nl80211_get_key()

Coverity pointed out that in the (practically impossible)
error case we leak the message - fix this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-commit: 9fe271af7d4de96471c5aaee2f4d0d1576050497
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Change-Id: I78c3631eabd04e86872faf65fa1e401dadb35a75
Signed-off-by: Ahmad Kholaif <akholaif@codeaurora.org>