m4: Fix missing with_acl variable
m4: Fix missing with_acl variable

This commit fixes an acl missing variable. The virt-acl.m4 inside the
macro directory does not contain the variable 'with_acl'. So, it is
being set as an empty string "with_acl=''". This is causing a missing
option during the configuration, even if you have acl libs installed.

Signed-off-by: Julio Faracco <a9e27ab562b8d02c0041eb70cde6fe3858219fb7@gmail.com>

andreabolognani/libvirt,crobinso/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,eskultety/libvirt,datto/libvirt,olafhering/libvirt,jardasgit/libvirt,jfehlig/libvirt,nertpinx/libvirt,libvirt/libvirt,nertpinx/libvirt,datto/libvirt,crobinso/libvirt,andreabolognani/libvirt,crobinso/libvirt,jfehlig/libvirt,andreabolognani/libvirt,libvirt/libvirt,datto/libvirt,crobinso/libvirt,eskultety/libvirt,zippy2/libvirt,fabianfreyer/libvirt,datto/libvirt,nertpinx/libvirt,jardasgit/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,eskultety/libvirt,eskultety/libvirt,VenkatDatta/libvirt,libvirt/libvirt,andreabolognani/libvirt,olafhering/libvirt,fabianfreyer/libvirt,datto/libvirt,zippy2/libvirt,jardasgit/libvirt,olafhering/libvirt,libvirt/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,jfehlig/libvirt,andreabolognani/libvirt,zippy2/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,olafhering/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,eskultety/libvirt,fabianfreyer/libvirt,zippy2/libvirt,jfehlig/libvirt