thunderbolt: Fix compile-time warning
The Thunderbolt panel warns about explicit_bzero() not being available but never checked for it.
gnome-control-center/panels/thunderbolt/bolt-str.c: In function ‘bolt_erase_n’: gnome-control-center/panels/thunderbolt/bolt-str.c:33:4: warning: #warning no explicit bzero, using fallback [-Wcpp] #warning no explicit bzero, using fallback ^~~~~~~
Closes: #286 (closed)