bison: add autotools as build requires

M4 version on SLC6 is too old or is unsupported. Add autotools
package as BuildRequires to Bison.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #141 from davidlt/IB/CMSSW_7_0_X/stable

[CMSSW_7_0_X] Add autotools to Bison (System M4 is not supported on SLC6)