install: locate rpmlint rc file with -r in mrel

Update mrel script to locate rpmlint rc file with the -r command-line
switch as -f is not recognized anymore on rpmlint v2.

Author: xdelaruelle

script/mrel

@@ -238,7 +238,7 @@ file delete log-gz log-bz log-win $prevdistgz distfiles distfiles-win\
    log-prev-gz distfiles-prev $prevdistwin log-prev-win distfiles-win-prev
 
 # check generated RPM spec file
-runcmd >@stdout rpmlint -f contrib/rpm/environment-modules.rpmlintrc\
+runcmd >@stdout rpmlint -r contrib/rpm/environment-modules.rpmlintrc\
    contrib/rpm/environment-modules.spec
 quitorcont