(packaging) Fixup redhat spec file

Add needed slash in pathing in rpm specfile and replace undefined _real_name
macro with _name macro. Add RPM_BUILD_ROOT to install target so it exists. Also
create the opt/puppet/share/puppet-dashboard/public directory so it can be
linked into.
(packaging) Add NO_BRP_STALE_LINK_ERROR

Add the NO_BRP_STALE_LINK_ERROR flag to the specfile to allow clean sles
building. The link will exist after install (the flag overrides a failed build
due to broken links in a package).
Merge pull request #7 from haus/redhat_sles_spec_fixups

Redhat sles spec fixups