packaging: remove generated files, use reconfigure macro

Remove unneeded files supposed to be generated at configure
time, and use the %reconfigure macro instead of %configure.
This will allow to modify files such as "configure.ac" or
"Makefile.am".

Change-Id: I5ef2b2bced4f638e6d038fdf163606a0c96ee54b
Signed-off-by: Manuel Bachmann <manuel.bachmann@open.eurogiciel.org>