virtpm: Fix @path handling in virTPMEmulatorInit()
virtpm: Fix @path handling in virTPMEmulatorInit()

This function finds "swtmp", "swtpm_setup" and "swtpm_ioctl"
binaries in $PATH and stores resolved paths in global variables
so that they can be obtainer later. Anyway, the resolved path is
marked as g_autofree and to avoid its freeing later on in the
function the variable is set to NULL manually. Well, we have
g_steal_pointer() for that.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

jfehlig/libvirt,nertpinx/libvirt,nertpinx/libvirt,zippy2/libvirt,libvirt/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,zippy2/libvirt,crobinso/libvirt,nertpinx/libvirt,jfehlig/libvirt,crobinso/libvirt,crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,zippy2/libvirt,libvirt/libvirt,libvirt/libvirt,nertpinx/libvirt,zippy2/libvirt,libvirt/libvirt,olafhering/libvirt,jfehlig/libvirt,olafhering/libvirt