mount: output it before replacing lastError
mount: output it before replacing lastError

Signed-off-by: Zhou Hao <f577ade201aa03d612c19915a089dc6084d45cd9@cn.fujitsu.com>

nalind/buildah-1,rhatdan/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,ipbabble/buildah,rhatdan/buildah,rhatdan/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,projectatomic/buildah,nalind/buildah,nalind/buildah-1,nalind/buildah,ipbabble/buildah,nalind/buildah-1,TomSweeneyRedHat/buildah