Anchor the regexp match

Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4483)

apps/CA.pl.in

@@ -127,7 +127,7 @@ if ($WHAT eq '-newcert' ) {
     # create a pre-certificate
     $RET = run("$REQ -x509 -precert -keyout $NEWKEY -out $NEWCERT $DAYS");
     print "Pre-cert is in $NEWCERT, private key is in $NEWKEY\n" if $RET == 0;
-} elsif ($WHAT =~ /\-newreq(\-nodes)?/ ) {
+} elsif ($WHAT =~ /^\-newreq(\-nodes)?$/ ) {
     # create a certificate request
     $RET = run("$REQ -new $1 -keyout $NEWKEY -out $NEWREQ $DAYS $EXTRA{req}");
     print "Request is in $NEWREQ, private key is in $NEWKEY\n" if $RET == 0;