Revert "extensionSystem: handle reloading broken extensions"

Both reloadExtensions() and enableExtensions() are already expected
to catch extension errors. If they don't, this is the bug that
should be fixed instead of catching unhandled exceptions in the
caller.

This reverts commit ff425d1db7.

https://bugzilla.gnome.org/show_bug.cgi?id=781728

js/ui/extensionSystem.js

@@ -282,20 +282,12 @@ function _onVersionValidationChanged() {
     // temporarily disable them all
     enabledExtensions = [];
     for (let uuid in ExtensionUtils.extensions)
-        try {
         reloadExtension(ExtensionUtils.extensions[uuid]);
-        } catch(e) {
-            logExtensionError(uuid, e);
-        }
     enabledExtensions = getEnabledExtensions();
 
     if (Main.sessionMode.allowExtensions) {
         enabledExtensions.forEach(function(uuid) {
-            try {
             enableExtension(uuid);
-            } catch(e) {
-                logExtensionError(uuid, e);
-            }
         });
     }
 }