check siginfo si_code to verify that SIGUSR2 comes from user

When VT switching away and back, the kernel uses SIGUSR1 and SIGUSR2
to notify us of a vt switch event. That same signal was being trapped
here to toggle display of the 'fps' window. If we check the signal's
si_code, we can tell if this signal came from the kernel (as in vt
switch) or from the user (as is sent in 'kill'). This fixes the issue
of VT-switching back and forth under DRM would cause the compositor
'fps' display to appear.

Signed-off-by: Chris Michael <cpmichael@osg.samsung.com>

src/bin/e_comp.c

@@ -817,6 +817,12 @@ _e_comp_key_down(void *data EINA_UNUSED, int type EINA_UNUSED, Ecore_Event_Key *
 static Eina_Bool
 _e_comp_signal_user(void *data EINA_UNUSED, int type EINA_UNUSED, Ecore_Event_Signal_User *ev)
 {
+   siginfo_t sig;
+
+   sig = ev->data;
+   /* anything sent via 'kill' will set this code to SI_USER */
+   if (sig.si_code != SI_USER) return ECORE_CALLBACK_PASS_ON;
+
    if (ev->number == 1)
      {
         // e uses this to pop up config panel