Compilation on mingw was warning about %lld use in fprintf, and
in the gnulib strptime module about dead labels.

* tools/virsh.c (vshPrint): Change redirect.
(vshPrintExtra): Allow use within vshPrint.  Avoid fprintf on
arbitrary formats, since we aren't using gnulib module; instead,
use virVasprintf to pre-format.
(vshError): Likewise.
* .gnulib: Update to latest, for mingw strptime warning fix.
Reported by Matthias Bolte.