src: remove extraneous dot

This got accidentally added when landing original commit

PR-URL: https://github.com/nodejs/node/pull/12626
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Nikolai Vavilov <vvnicholas@gmail.com>

src/node.cc

@@ -53,7 +53,7 @@
 #endif
 
 #include <errno.h>
-#include <fcntl.h>. // _O_RDWR
+#include <fcntl.h>  // _O_RDWR
 #include <limits.h>  // PATH_MAX
 #include <locale.h>
 #include <signal.h>