rcutorture: Fix bug in reporting Kconfig mis-settings

Kconfig "select" clauses can defeat Kconfig-fragment file attempts to
clear a given Kconfig variable, and dependencies can defeat attempts to
set a given Kconfig variable.  Because "select" clauses and dependencies
can be added at any time, there needs to be a way to verify that the
Kconfig-fragment file's requests were honored.  And there is, except
that it is buggy.  This commit therefore provides the needed fix.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

tools/testing/selftests/rcutorture/bin/configcheck.sh

@@ -27,7 +27,7 @@ cat $1 > $T/.config
 
 cat $2 | sed -e 's/\(.*\)=n/# \1 is not set/' -e 's/^#CHECK#//' |
 awk	'
-BEGIN	{
+{
 		print "if grep -q \"" $0 "\" < '"$T/.config"'";
 		print "then";
 		print "\t:";