openssl: bring back RPM_OPT_FLAGS in %install step

Bring back RPM_OPT_FLAGS in %install step. RPM_OPT_FLAGS is defined
in %build and %install steps and is identical.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
root: drop %ifos macros

Stop using %ifarch and %ifos macros. Use %cmsplatf to figure out
operating system, architecture and/or compiler.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>