redhat: convert rpm spec file to make install

redhat: convert rpm spec file to make install

Convert the build and install from the deprecated 'make dest' to the
modern 'make install' method.

* Clarify the install section by unrolling the shell scripts,
  reorganizing, and improving the comments.
* Remove the gzip glob of the man pages; rpmbuild automatically
  compresses the man pages and will handle symlinks correctly.
* Remove the generated temporary list file and specify files directly.
* Remove the extra tar commands to install the man pages out of the doc
  directory; 'make install..' installs the man pagess.
* Remove code in the install section which determines the sysname. This is
  no longer needed during the install.
* Update the kernel module install commands to accommodate the
  conversion from 'make dest'.

Change-Id: I97ec80185a2b11704b27ea74941b50ff4a5aca8c
Reviewed-on: https://gerrit.openafs.org/12594
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: Benjamin Kaduk <kaduk@mit.edu>