torture: Simplify exit-code plumbing for kvm-recheck.sh and kvm-find-errors.sh

This commit simplifies exit-code plumbing.  It makes kvm-recheck.sh return
the value 1 for a build error and 2 for a runtime error.  It also makes
kvm-find-errors.sh avoid checking runtime files for --build-only runs.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh

@@ -46,6 +46,7 @@ fi
 if grep -q -e "--buildonly" < ${rundir}/log
 then
 	echo Build-only run, no console logs to check.
+	exit $editorret
 fi
 
 # Find console logs with errors

tools/testing/selftests/rcutorture/bin/kvm-recheck.sh

@@ -87,15 +87,16 @@ do
 	fi
 done
 EDITOR=echo kvm-find-errors.sh "${@: -1}" > $T 2>&1
-ret=$?
 builderrors="`tr ' ' '\012' < $T | grep -c '/Make.out.diags'`"
 if test "$builderrors" -gt 0
 then
 	echo $builderrors runs with build errors.
+	ret=1
 fi
 runerrors="`tr ' ' '\012' < $T | grep -c '/console.log.diags'`"
 if test "$runerrors" -gt 0
 then
 	echo $runerrors runs with runtime errors.
+	ret=2
 fi
 exit $ret