[FIX] component: better templateId for multiple subcomponents

Of course, the templateId computation is kind of tricky.  Here, an issue
occurred because the templateId did not take the componentId into
account when we were in a loop, but with no keyed parent.

This meant that multiple sub components shared the same templateId,
confusing the vdom algorithm.

src/component/directive.ts

@@ -245,7 +245,7 @@ QWeb.addDirective({
       ? `key${keyID}`
       : ctx.inLoop
       ? ctx.currentKey
-        ? `String(${ctx.currentKey} + '_k_' + i)`
+        ? `String(${ctx.currentKey} + '_k_' + i + '_c_' + ${componentID} )`
         : `String(-${componentID} - i)`
       : String(componentID);
     if (ctx.allowMultipleRoots) {