Hoist, and delay, the saving of import tag while opening the file...

... so that AudacityProject::AudacityProject no longer has a path in the
static call graph that reaches block file write operations that might throw.

So it is easier to prove that other functions, calling that, don't throw.

Also delay the possibly thowing save of the import until after certain other
steps in the file opening procedure.

src/Project.cpp

@@ -3124,6 +3124,8 @@ void AudacityProject::OpenFile(const wxString &fileNameArg, bool addtohistory)
          wxGetApp().AddFileToHistory(fileName);
       }
 
+      bool saved = false;
+
       if (mIsRecovered)
       {
          // This project has been recovered, so write a NEW auto-save file
@@ -3182,9 +3184,20 @@ void AudacityProject::OpenFile(const wxString &fileNameArg, bool addtohistory)
             //    this->PushState(_("Project checker repaired file"), _("Project Repair"));
 
             if (status & FSCKstatus_SAVE_AUP)
-               this->Save();
+               this->Save(), saved = true;
          }
       }
+
+      if (mImportXMLTagHandler) {
+         if (!saved)
+            // We processed an <import> tag, so save it as a normal project,
+            // with no <import> tags.
+            this->Save();
+
+         // Shouldn't need it any more.
+         mImportXMLTagHandler.reset();
+      }
+
    } else {
       // Vaughan, 2011-10-30:
       // See first topic at http://bugzilla.audacityteam.org/show_bug.cgi?id=451#c16.
@@ -4298,14 +4311,6 @@ For an audio file that will open in other apps, use 'Export'.\n"),
 
 void AudacityProject::InitialState()
 {
-   if (mImportXMLTagHandler) {
-      // We processed an <import> tag, so save it as a normal project, with no <import> tags.
-      this->Save();
-
-      // Shouldn't need it any more.
-      mImportXMLTagHandler.reset();
-   }
-
    GetUndoManager()->ClearStates();
 
    GetUndoManager()->PushState(GetTracks(), mViewInfo.selectedRegion, mTags,