Revert "kinput: allocate enough space for null character."

This reverts commit 531785dd74.

The above commit breaks Xephyr option parsing.  Andrzej writes:

  Xephyr -retro -keybd evdev,,device=/dev/input/event2,xkbrules=evdev,xkbmodel=evdev,xkblayout=pl -mouse evdev,,device=/dev/input/event1 :3

  results in:

  <snip>
  Pointer option key (device=) of value (/dev/input/event1) not assigned!
  Kbd option key (device=) of value (/dev/input/event2) not assigned!
  Kbd option key (xkbrules=) of value (evdev) not assigned!
  Kbd option key (xkbmodel=) of value (evdev) not assigned!
  Kbd option key (xkblayout=) of value (pl) not assigned!
  <snip>

  The effect of the patch is that the "key=value" pairs are parsed in such
  a way that the key is added an "equals" sign to it and we end up with
  keys like "device=" instead of "device". This in turn has effect on
  KdParsePointerOptions and KdParseKbdOptions: the key does not match
  any choice presented in the "switch" statement, and so "Pointer/Kbd
  option key (...) of value (...) not assigned!" happens, making all
  "key=value" options inaccessible to the user. Reverting the patch makes
  them available again.

Reference: http://bugs.debian.org/689246
Reported-by: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
Signed-off-by: Julien Cristau <jcristau@debian.org>
Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Søren Sandmann <ssp@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

hw/kdrive/src/kinput.c

@@ -1034,7 +1034,7 @@ KdGetOptions(InputOption **options, char *string)
 
     if (strchr(string, '=')) {
         tam_key = (strchr(string, '=') - string);
-        key = strndup(string, tam_key + 1);
+        key = strndup(string, tam_key);
         if (!key)
             goto out;