In new process code, move from model where qemuProcessQMP struct can be
used to activate a series of Qemu processes to model where one
qemuProcessQMP struct is used for one and only one Qemu process.

By allowing only one process activation per qemuProcessQMP struct, the
struct can safely store process outputs like status and stderr, without
being overwritten, until qemuProcessQMPFree is called.

By doing this, process outputs like status and stderr can remain stored
in the qemuProcessQMP struct without being overwritten by subsequent
process activations.

The forceTCG parameter (use / don't use KVM) will be passed when the
qemuProcessQMP struct is initialized since the qemuProcessQMP struct
won't be reused.
Signed-off-by: NChris Venteicher <cventeic@redhat.com>
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>