Fix missing `error` variable in the progress bar

fda-ui/components/QueryList.vue

 <template>
   <div>
-    <v-progress-linear v-if="loading" :indeterminate="!error" />
+    <v-progress-linear v-if="loading" />
     <v-tabs-items>
       <v-card v-if="!loading && queries.length === 0" flat>
         <v-card-title>

fda-ui/components/dialogs/PersistQuery.vue

@@ -65,7 +65,7 @@ export default {
     return {
       formValid: false,
       loading: false,
-      error: false,
+      error: false, // XXX: `error` is never changed
       visibility: [{
         name: 'Public',
         value: 'EVERYONE'

fda-ui/components/dialogs/TimeTravel.vue

@@ -49,7 +49,7 @@ export default {
     return {
       formValid: false,
       loading: false,
-      error: false,
+      error: false, // XXX: `error` is never changed
       date: null,
       time: null
     }

fda-ui/pages/container/_container_id/database/_database_id/info.vue

 <template>
   <div v-if="db">
     <DBToolbar />
-    <v-progress-linear v-if="loading" :indeterminate="!error" />
+    <v-progress-linear v-if="loading" />
     <v-tabs-items v-if="!loading" v-model="tab">
       <v-tab-item>
         <v-card flat>

fda-ui/pages/container/_container_id/database/_database_id/table/_table_id/index.vue

@@ -77,6 +77,7 @@ export default {
       timeMenu: false,
       pickVersionDialog: null,
       version: null,
+      error: false, // XXX: `error` is never changed
       options: {
         page: 1,
         itemsPerPage: 10

fda-ui/pages/login.vue

@@ -57,7 +57,7 @@ export default {
   data () {
     return {
       loading: false,
-      error: false,
+      error: false, // XXX: `error` is never changed
       valid: false,
       loginAccount: {
         username: null,

fda-ui/pages/signup.vue

@@ -91,7 +91,7 @@ export default {
   data () {
     return {
       loading: false,
-      error: false,
+      error: false, // XXX: `error` is never changed
       valid: false,
       privacy: false,
       consent: false,