qemu: drop unused variable
qemu: drop unused variable

The g_auto conversion made clang realize the variable is unused:
../../src/qemu/qemu_domain.c:10349:36: error: unused variable
    'cfg' [-Werror,-Wunused-variable]
    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Fixes: 20fa2bc6e52e01feaf39d12d38bcf8eaec4c9a46

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