[libvirt] VIR_ERROR and VIR_DEBUG normalization

Most of the following changes have been induced automatically. The few outliers done manually are marked as such. [PATCH 01/10] maint: use VIR_ERROR0 rather than VIR_ERROR with a bare "%s" [PATCH 02/10] maint: mark translatable string args of VIR_ERROR0 [PATCH 03/10] maint: mark translatable string args of VIR_ERROR [PATCH 04/10] maint: VIR_ERROR/VIR_ERROR0: mark up the remaining ones manually [PATCH 05/10] maint: more of same, but manual: convert VIR_ERROR("%s" to VIR_ERROR0( [PATCH 06/10] maint: change "" in err ? err->message : "" to _("unknown error"), ... [PATCH 07/10] maint: enforce policy wrt VIR_ERROR and VIR_ERROR0 [PATCH 08/10] maint: don't mark VIR_DEBUG or VIR_DEBUG0 diagnostics for translation [PATCH 09/10] maint: enforce policy wrt VIR_DEBUG and VIR_DEBUG0 [PATCH 10/10] maint: update po/POTFILES.in