Don't reset intro-point creation rate-limiting timer

Previously, we would reset it at the drop of a hat -- every time a second
passes without any of the intro-point circs already launched for the
service failing.

Fixes bug 4607.

changes/bug4607

@@ -0,0 +1,9 @@
+  o Minor bugfixes:
+
+    - Don't launch more than 10 (service-side) introduction-point
+      circuits for a hidden service in five minutes.  Previously, we
+      would consider launching more introduction-point circuits if at
+      least one second had passed without any introduction-point
+      circuits failing.  Fixes bug 4607; bugfix on 0.0.7rc1.
+
+

src/or/rendservice.c

@@ -2270,14 +2270,6 @@ rend_services_introduce(void)
 
     if (!intro_point_set_changed &&
         (n_intro_points_unexpired >= service->n_intro_points_wanted)) {
-      /* We have enough intro circuits in progress, and none of our
-       * intro circuits have died since the last call to
-       * rend_services_introduce!  Start a fresh period and reset the
-       * circuit count.
-       *
-       * XXXX WTF? */
-      service->intro_period_started = now;
-      service->n_intro_circuits_launched = 0;
       continue;
     }