XQuartz: Remove the redundant xquartz_resetenv_display

unsetenv(DISPLAY) takes care of this for us anyway
(cherry picked from commit d2263645d8)

hw/xquartz/X11Controller.m

@@ -52,8 +52,6 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 
-BOOL xquartz_resetenv_display = NO;
-
 @implementation X11Controller
 
 - (void) awakeFromNib
@@ -353,7 +351,7 @@ BOOL xquartz_resetenv_display = NO;
     newargv[3] = NULL;
     
     s = getenv("DISPLAY");
-    if (xquartz_resetenv_display || s == NULL || s[0] == 0) {
+    if (s == NULL || s[0] == 0) {
         snprintf(buf, sizeof(buf), ":%s", display);
         setenv("DISPLAY", buf, TRUE);
     }

hw/xquartz/mach-startup/bundle-main.c

@@ -62,8 +62,6 @@ void DarwinListenOnOpenFD(int fd);
 
 extern int noPanoramiXExtension;
 
-extern int xquartz_resetenv_display;
-
 #define DEFAULT_CLIENT X11BINDIR "/xterm"
 #define DEFAULT_STARTX X11BINDIR "/startx"
 #define DEFAULT_SHELL  "/bin/sh"
@@ -429,9 +427,6 @@ static int startup_trigger(int argc, char **argv, char **envp) {
     if((s = getenv("DISPLAY"))) {
         fprintf(stderr, "X11.app: Could not connect to server (DISPLAY=\"%s\", unsetting).  Starting X server.\n", s);
         unsetenv("DISPLAY");
-        
-        /* This tells X11Controller to not use the environment's DISPLAY and reset it based on the server's display */
-        xquartz_resetenv_display = 1;
     } else {
         fprintf(stderr, "X11.app: Could not connect to server (DISPLAY is not set).  Starting X server.\n");
     }