Cleaned up RPM files

I tested this spec file with mock on RHEL and it now works out of the box.  The new spec file would require a change in naming conventions for the github archives.  Files would need to be named barnyard2-{version}.tar.gz instead of v2-{version}.tar.gz.  The v2 naming scheme breaks RPM naming conventions and caused my build attempts to error out.  

The most important change is adding (noreplace) to the config files.  A yum update corrupted the sig_reference table by attempting to use the stock config file.

It may be better to move the conditional installs of database schemas into the autoconf/automake process.  I wasn't sure what SCHEMA_ACCESS is used for.  Should it be included in all barnyard2 installs?