package/aumix: bump version to 2.9.1

- rebased patch 0001
- added AUMIX_GETTEXTIZE = YES to solve
  *** error: gettext infrastructure mismatch: using a Makefile.in.in
  from gettext version 0.17 but the autoconf macros are from gettext
  version 0.19

Fixes
http://autobuild.buildroot.net/results/c8c/c8c7f9a799d1af507a6edd5e02b0bbc8b7b5d068/
http://autobuild.buildroot.net/results/67e/67e6d29e6d6f8d4967a74ec70a754a5b24afc0ce/


and others

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>