Clear O_RDWR bit

Author: timgimyee

lib/File/Temp.pm

@@ -503,15 +503,15 @@ sub _gettemp {
       my $open_success = undef;
       if ( $^O eq 'VMS' and $options{"unlink_on_close"} && !$KEEP_ALL) {
         my $flags = $OPENFLAGS;
-        $flags = ($flags ^ O_RDWR) | O_WRONLY if $options{write_only};
+        $flags = ($flags & ~O_RDWR) | O_WRONLY if $options{write_only};
         # make it auto delete on close by setting FAB$V_DLT bit
         $fh = VMS::Stdio::vmssysopen($path, $flags, 0600, 'fop=dlt');
         $open_success = $fh;
       } else {
         my $flags = ( ($options{"unlink_on_close"} && !$KEEP_ALL) ?
                       $OPENTEMPFLAGS :
                       $OPENFLAGS );
-        $flags = ($flags ^ O_RDWR) | O_WRONLY if $options{write_only};
+        $flags = ($flags & ~O_RDWR) | O_WRONLY if $options{write_only};
         $flags |= $LOCKFLAG if (defined $LOCKFLAG && $options{use_exlock});
         $open_success = sysopen($fh, $path, $flags, 0600);
       }