Handle exceptions thrown by Unity.Cecil on asset rename

When the VersionHandler activates a package it potentially renames
DLLs to the canonical name causing the DLL to be reimported.  In
some cases this can cause Unity.Cecil (as far I can tell they use this
to rewrite DLLs) to throw exceptions while processing the DLL which
are totally harmless as they DLL is imported and processed again
when AssetDatabase.Refresh() is executed.

BUG=34123612

Change-Id: I20e993aa0de8ff8b1075258d042ccf076b945ddf

Author: Stewart Miles

source/VersionHandler/src/VersionHandler.cs

@@ -401,15 +401,23 @@ public bool RenameAsset(string newFilename) {
                     return false;
                 }
             }
-            string error = AssetDatabase.RenameAsset(
-                filename, filenameComponents.basenameNoExtension);
-            if (!String.IsNullOrEmpty(error)) {
-                UnityEngine.Debug.LogError(
-                    "Failed to rename asset " + filename + " to " +
-                    newFilename + " (" + error + ")");
-                return false;
+            try {
+              string error = AssetDatabase.RenameAsset(
+                  filename, filenameComponents.basenameNoExtension);
+              if (!String.IsNullOrEmpty(error)) {
+                  UnityEngine.Debug.LogError(
+                      "Failed to rename asset " + filename + " to " +
+                      newFilename + " (" + error + ")");
+                  return false;
+              }
+              AssetDatabase.ImportAsset(newFilename);
+            } catch (Exception) {
+                // Unity 5.3 and below can end up throw all sorts of
+                // exceptions here when attempting to reload renamed
+                // assemblies.  Since these are completely harmless as
+                // everything will be reloaded and exceptions will be
+                // reported upon AssetDatabase.Refresh(), ignore them.
             }
-            AssetDatabase.ImportAsset(newFilename);
             filename = newFilename;
             UpdateAssetLabels();
             return true;