configure: Replace - in version string with _ to fix rpm build.

"-" is not allowed as version number for RPM.

This bug was introduced by commit a4609b ("configure,spec: Change
version number to 14.12-dev.").

Signed-off-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
spec: el7 support.

Signed-off-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Merge pull request #699 from project-hatohol/spec-20141009b

Spec 20141009b - fix and support for centos7