spice-common: remove version construction
spice-common: remove version construction

Version string isn't used anywhere in spice-common, and there's
no version for spice-common module per se, either.  Hoever,
configure.ac has this:

 AC_INIT([spice-common],
         [m4_esyscmd(build-aux/git-version-gen .tarball-version)],
         [spice-devel@lists.freedesktop.org])

But since git-version-gen script is not provided in spice-common
module, multiple error messages are produced when generating
configure (running autogen/autoreconf), like this:

  sh: ./build-aux/git-version-gen: not found

(repeated about 50 times).

The following trivial patch removes usage of build-aux/git-version-gen
from AC_INIT and replaces it with a string "noversion", to stop
these scary messages from being produced.

Signed-off-by: Michael Tokarev <389bd06664b699d49ce291f515b98373073ad5f4@tls.msk.ru>

SPICE/spice-common,freedesktop-unofficial-mirror/spice__spice-common,Fantu/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,elmarco/spice-common,Fantu/spice-common,elmarco/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,Fantu/spice-common,fgouget/spice-common,SPICE/spice-common,fgouget/spice-common,SPICE/spice-common,elmarco/spice-common,freedesktop-unofficial-mirror/spice__spice-common,Fantu/spice-common,elmarco/spice-common