The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.
Format the address using the helper instead of having similar code in
multiple places.
This patch also fixes leak of the MAC address string in
ebtablesRemoveForwardAllowIn() and ebtablesAddForwardAllowIn() in
src/util/virebtables.c
