[gtk-vnc] meson: Fix configuration failure with -Dwith-vala=disabled

[Daniel P. Berrange <dberrange src gnome org>]

commit bdab05584bab5c2ecdd508df49b03e80aedd19fc
Author: Matt Turner <mattst88 gmail com>
Date:   Wed Apr 28 17:16:54 2021 -0400

    meson: Fix configuration failure with -Dwith-vala=disabled
    
    Otherwise with_vala is not defined, and meson setup results in
    
        src/meson.build:169:5: ERROR: Unknown variable "with_vala".

 meson.build | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index e9829e6..777876c 100644
--- a/meson.build
+++ b/meson.build
@@ -318,12 +318,11 @@ gir = find_program('g-ir-scanner', required: get_option('introspection'))
 with_gir = gir.found()
 
 vala_opt = get_option('with-vala')
+with_vala = false
 if not vala_opt.disabled()
   if not with_gir
     if vala_opt.enabled()
       error('Vala API requires GObject introspection (-Dintrospection=true)')
-    else
-      with_vala = false
     endif
   else
     with_vala = add_languages('vala', required: vala_opt)