gbm: cleanup memory leaks
gbm: cleanup memory leaks

Avoid leaking udev and udev_enumerate. Spotted while
searching for invalid memory access in the wgl platform.

Signed-off-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>
Reviewed-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@linux.intel.com>

janesma/waffle,yinquan529/waffle-gl-waffle,evelikov/waffle,chadversary/waffle,janesma/waffle,yinquan529/waffle-gl-waffle,fjhenigman/waffle,fjhenigman/waffle,maurossi/waffle,chadversary/waffle,yinquan529/waffle-gl-waffle,dcbaker/waffle,waffle-gl/waffle,janesma/waffle,waffle-gl/waffle,dcbaker/waffle,waffle-gl/waffle,waffle-gl/waffle,maurossi/waffle,evelikov/waffle,fjhenigman/waffle,chadversary/waffle,evelikov/waffle,maurossi/waffle,dcbaker/waffle