util: fix check for iscsi initiator copy
util: fix check for iscsi initiator copy

virStorageSourceInitiatorCopy propagates the return
value from VIR_STRDUP, which returns 1 on a successful
copy.

Only error out on < 0, not non-zero values.

Fixes: 9ea3fdc6e90a96e3d7d7aeb9867e8f0a3992b7c6

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

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