Refactor promise chains to avoid .finally

Use of .then following a use of .catch works the same as .finally.

Bug: Issue 9650
Change-Id: Ic83b21e357141fbe889ad4e82c59eef222fa4847
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js
index 982c40a..d84dec5 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js
@@ -224,7 +224,7 @@
             this.$.reporting.dashboardDisplayed();
           }).catch(err => {
             console.warn(err);
-          }).finally(() => { this._loading = false; });
+          }).then(() => { this._loading = false; });
     },
 
     /**
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
index 46280d4..4f9de6f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
@@ -254,17 +254,20 @@
         return this._loadDiffAssets(diff);
       });
 
-      return Promise.all([diffRequest, assetRequest]).then(results => {
-        const diff = results[0];
-        if (!diff) {
-          return Promise.resolve();
-        }
-        this.filesWeblinks = this._getFilesWeblinks(diff);
-        this._diff = diff;
-        return this._renderDiffTable();
-      }).finally(() => {
-        this._loading = false;
-      });
+      return Promise.all([diffRequest, assetRequest])
+          .then(results => {
+            const diff = results[0];
+            if (!diff) {
+              return Promise.resolve();
+            }
+            this.filesWeblinks = this._getFilesWeblinks(diff);
+            this._diff = diff;
+            return this._renderDiffTable();
+          })
+          .catch(err => {
+            console.warn('Error encountered loading diff:', err);
+          })
+          .then(() => { this._loading = false; });
     },
 
     /** Cancel any remaining diff builder rendering work. */