Handle dismiss of sign window with a new one

app/src/containers/StartTopicContainer.js

@@ -120,7 +120,7 @@ class StartTopicContainer extends Component {
                 placeholder="Post"
                 id="topicMessageInput"
                 rows={5}
-                autoHeight
+                autoheight="true"
                 onChange={this.handleInputChange}
               />]
             }

app/src/utils/EthereumIdentityProvider.js

@@ -10,8 +10,15 @@ class EthereumIdentityProvider {
   async getId () { return this.id; }
 
   async signIdentity (data) {
+    while(true){  //Insist (e.g. if user dismisses dialog)
+      try{
         return await web3.eth.personal.sign(data, this.id,"");  //Password not required for MetaMask
       }
+      catch (e) {
+        console.error("Failed to sign data.");
+      }
+    }
+  }
 
   static async verifyIdentity (identity) {
     // Verify that identity was signed by the ID