Fix a bridge segfault

When we enabled support to change statistic options without restarting
Tor we forgot to initialize geoip_countries. Fix that.

changes/bug1964

@@ -0,0 +1,3 @@
+  o Major bugfixes:
+    - Fix a segfault that can happen when using bridges. Fixes bug 1964;
+      bugfix on 0.2.2.15-alpha.

src/or/geoip.c

@@ -254,6 +254,8 @@ geoip_get_country_by_ip(uint32_t ipaddr)
 int
 geoip_get_n_countries(void)
 {
+  if (!geoip_countries)
+    init_geoip_countries();
   return (int) smartlist_len(geoip_countries);
 }