Change default of --modify-window on Cygwin from 2 to 1 because that's all

that's needed on FAT filesystems.  NTFS filesystems can do with a window of
0, but it shouldn't hurt because it's highly unlikely that any given file
will be modified within one second of the time that rsync last copied it.

NEWS

@@ -31,7 +31,7 @@ rsync changes since last release
     * Properly support IPv6 addresses in the rsyncd.conf "hosts allow"
       and "hosts deny" fields.  (Hideaki Yoshifuji)
 
-    * Set the default value of --modify-window to 2 on Cygwin.  (Lapo
+    * Set the default value of --modify-window to 1 on Cygwin.  (Lapo
       Luchini)
 
     * Ignore errors from chmod when -p/-a/--preserve-perms is not set.

configure.in

@@ -249,7 +249,7 @@ fi
 
 AC_MSG_CHECKING([default value for --modify-window])
 case $host_os in
-	*cygwin* ) DEFAULT_MODIFY_WINDOW=${DEFAULT_MODIFY_WINDOW:-2};;
+	*cygwin* ) DEFAULT_MODIFY_WINDOW=${DEFAULT_MODIFY_WINDOW:-1};;
 	       * ) DEFAULT_MODIFY_WINDOW=${DEFAULT_MODIFY_WINDOW:-0};;
 esac
 AC_MSG_RESULT($DEFAULT_MODIFY_WINDOW)