glx: Fix for commit 2c86668694.

Ian suggested these changes in his review and I made them, but I pushed
the old version of the patch.
diff --git a/src/glx/indirect_vertex_array.c b/src/glx/indirect_vertex_array.c
index a707343..c81aae6 100644
--- a/src/glx/indirect_vertex_array.c
+++ b/src/glx/indirect_vertex_array.c
@@ -207,6 +207,7 @@
    arrays->arrays = calloc(array_count, sizeof(struct array_state));
 
    if (arrays->arrays == NULL) {
+      state->array_state = NULL;
       free(arrays);
       __glXSetError(gc, GL_OUT_OF_MEMORY);
       return;
@@ -295,6 +296,7 @@
                           * __GL_CLIENT_ATTRIB_STACK_DEPTH);
 
    if (arrays->stack == NULL) {
+      state->array_state = NULL;
       free(arrays->arrays);
       free(arrays);
       __glXSetError(gc, GL_OUT_OF_MEMORY);