ui/shader: fix potential leak of shader on error

Value of 0 for program and shaders are silently ignored and indicate error.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/ui/shader.c b/ui/shader.c
index e8b8d32..4c80fc8 100644
--- a/ui/shader.c
+++ b/ui/shader.c
@@ -130,15 +130,17 @@
 static GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src,
                                                   const GLchar *frag_src)
 {
-    GLuint vert_shader, frag_shader, program;
+    GLuint vert_shader, frag_shader, program = 0;
 
     vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src);
     frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src);
     if (!vert_shader || !frag_shader) {
-        return 0;
+        goto end;
     }
 
     program = qemu_gl_create_link_program(vert_shader, frag_shader);
+
+end:
     glDeleteShader(vert_shader);
     glDeleteShader(frag_shader);