LU-15521 spec: fix bare words error with rpm 4.16

LU-15521 spec: fix bare words error with rpm 4.16

RPM 4.16 removed support for bare words in expressions
(eg a == b needs to be "a" == "b" now). The change is
backward compatible. More changes are in:
https://rpm.org/wiki/Releases/4.16.0

This patch accommodates the above change and fixes more
errors/warnings:
- E: specfile-error error: bare words are no longer supported,
     please use "...":  redhat=="redhat" || redhat=="fedora"
- E: specfile-error warning: extra tokens at the end of %else
     directive in line 140:  %else #for Suse
- W: macro-in-comment %optflags
- W: macro-in-comment %{name}

Lustre-change: https://review.whamcloud.com/46471
Lustre-commit: 597a6bf9e085150dd57eb727859b114deb8979cb

Test-Parameters: trivial

Change-Id: I725c47f62be7762a89e5919fd2865e2fb2ced407
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/47772
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>