Avoid unnecessary warning about missing :key

:key is not necessary in seqs in render-to-string et al.

src/reagent/impl/template.cljs

@@ -282,7 +282,8 @@
       (warn "Reactive deref not supported in lazy seq, "
             "it should be wrapped in doall"
             (comp/comp-name) ". Value:\n" (pr-str x)))
-    (when (.' ctx :no-key)
+    (when (and (not comp/*non-reactive*)
+               (.' ctx :no-key))
       (warn "Every element in a seq should have a unique "
             ":key" (comp/comp-name) ". Value: " (pr-str x)))
     res))

test/reagenttest/testreagent.cljs

@@ -516,3 +516,12 @@
          (rstr [:div.foo [:p.bar.foo [:b.foobar "xy"]]])))
   (is (= (rstr [:div>p.bar.foo>a.foobar {:href "href"} "xy"])
          (rstr [:div [:p.bar.foo [:a.foobar {:href "href"} "xy"]]]))))
+
+
+(deftest test-key-warning
+  ;; Just make sure that seq without key dont print unnecessary
+  ;; debug messages
+  (r/render-to-static-markup [:div (for [x (range 5)]
+                                     [:p x])])
+  (r/render-to-string [:div (for [x (range 5)]
+                              [:p x])]))