virsh-domain: Drop support for old APIs in cmdSetmem and cmdSetmaxmem

virsh-domain: Drop support for old APIs in cmdSetmem and cmdSetmaxmem

Some of our really old APIs are missing @flags argument. We
introduced their variants with "Flags" suffix and wired some
logic into virsh to call the new variant only if necessary. This
enables virsh to talk to older daemon which may be lacking new
APIs.

However, in case of cmdSetmem() we are talking about v0.1.1
(virDomainSetMemory()) vs. v0.9.0 (virDomainSetMemoryFlags()) and
in case of cmdSetmaxmem() we are talking about v0.0.3
(virDomainSetMaxMemory()) vs v0.9.0 (virDomainSetMemoryFlags()).

Libvirt v0.9.0 was released more than 10 years ago and recently
we dropped support for RHEL-7 which has v4.5.0 (released ~3 years
ago). Thus it is not really necessary to have support in virsh
for such old daemons.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>