log: fix log_append_stderr()
log: fix log_append_stderr()

Log output currently looks like this:

	lxc-copy: debbdev/lxcdir.c: dir_clonepaths: 45 directories cannot be snapshotted.  Try aufs or overlayfs.

we rather want it to be:

	lxc-copy: deb: bdev/lxcdir.c: dir_clonepaths: 45 directories cannot be snapshotted.  Try aufs or overlayfs.

Signed-off-by: Christian Brauner <b487c2d908f9548b106d14dc6d7b88a1fc58d1d6@suse.de>

federicobriata/lxc,LynxChaus/lxc,ysbnim/lxc,terceiro/lxc,aeris/lxc,federicobriata/lxc,thmo/lxc,cjwatson/lxc,GreatFruitOmsk/lxc,federicobriata/lxc,cjwatson/lxc,caglar10ur/lxc,terceiro/lxc,ss1h2a3tw/lxc,caglar10ur/lxc,terceiro/lxc,hallyn/lxc,hfuCN/lxc,aeris/lxc,ss1h2a3tw/lxc,ss1h2a3tw/lxc,LynxChaus/lxc,ysbnim/lxc,hfuCN/lxc,thmo/lxc,thmo/lxc,cjwatson/lxc,GreatFruitOmsk/lxc,hallyn/lxc,caglar10ur/lxc,hallyn/lxc,aeris/lxc,LynxChaus/lxc,GreatFruitOmsk/lxc,hfuCN/lxc,ysbnim/lxc