shared/container: Moves global hex regex into specific function
shared/container: Moves global hex regex into specific function

To avoid having the regex loaded globally all the time.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,Skarlso/lxd,mjeanson/lxd,lxc/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,atxwebs/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,mjeanson/lxd,atxwebs/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,Skarlso/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,Skarlso/lxd,atxwebs/lxd,Skarlso/lxd,atxwebs/lxd,mjeanson/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd