selinux: Drop dead code in virSecuritySELinuxSetImageLabelInternal()

selinux: Drop dead code in virSecuritySELinuxSetImageLabelInternal()

Considering that at the virSecuritySELinuxSetFilecon() function can only
return 0 or -1 and so does the virSecuritySELinuxFSetFilecon(), the check
for '1' at the end of virSecuritySELinuxSetImageLabelInternal() is
effectively a dead code. Drop it.

Co-developed-by: sdl.qemu <sdl.qemu@linuxtesting.org>
Signed-off-by: Sergey Mironov <mironov@fintech.ru>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>