rpm: Build srpms without %dist in their name

rpm: Build srpms without %dist in their name

On RHEL6, %dist is set for all RPMS and SRPMS built on the system. This
leads to makesrpm.pl building SRPMS with .el6 in their release. As we
endeavour to use the same SRPM on all of our Fedora platforms, this is
less than ideal, so change makesrpm.pl to squash the setting of %dist
before building the RPM.

Reviewed-on: http://gerrit.openafs.org/4285
Reviewed-by: Alexander Ivan Redinger <aredinger@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit b0921071dd1b4d460d406985bba9619561444055)

Change-Id: I9e5bb2ce13378a0927763535d885a4728bd48f06
Reviewed-on: http://gerrit.openafs.org/4307
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>