Remove unnecessary variable from IllustrationView::OnCreate()

After removing the try/catch in the previous commit, this variable is
not really useful any more, so remove it to simplify the code and make
its logic more apparent.

* gpt_view.cpp: Likewise. [GWC]
* mec_view.cpp: Likewise. [GWC]

gpt_view.cpp

@@ -113,35 +113,22 @@ char const* gpt_view::menubar_xrc_resource() const
 }
 
 /// Pop up an input dialog; iff it's not cancelled, create a view.
-///
-/// Trap exceptions to ensure that this function returns 'false' on
-/// failure, lest wx's doc-view framework create a zombie view. See:
-///   https://lists.nongnu.org/archive/html/lmi/2008-12/msg00017.html
 
 bool gpt_view::OnCreate(wxDocument* doc, long int flags)
 {
-    bool has_view_been_created = false;
-    try
+    if(oe_mvc_dv_cancelled == edit_parameters())
         {
-        if(oe_mvc_dv_cancelled == edit_parameters())
-            {
-            return has_view_been_created;
-            }
-
-        has_view_been_created = ViewEx::DoOnCreate(doc, flags);
-        if(!has_view_been_created)
-            {
-            return has_view_been_created;
-            }
-
-        Run();
+        return false;
         }
-    catch(...)
+
+    if(!ViewEx::DoOnCreate(doc, flags))
         {
-        report_exception();
+        return false;
         }
 
-    return has_view_been_created;
+    Run();
+
+    return true;
 }
 
 wxPrintout* gpt_view::OnCreatePrintout()

illustration_view.cpp

@@ -148,29 +148,25 @@ char const* IllustrationView::menubar_xrc_resource() const
 
 bool IllustrationView::OnCreate(wxDocument* doc, long int flags)
 {
-    bool has_view_been_created = false;
-
     if(flags & LMI_WX_CHILD_DOCUMENT)
         {
         is_phony_ = true;
-        has_view_been_created = ViewEx::DoOnCreate(doc, flags);
-        return has_view_been_created;
+        return ViewEx::DoOnCreate(doc, flags);
         }
 
     if(oe_mvc_dv_cancelled == edit_parameters())
         {
-        return has_view_been_created;
+        return false;
         }
 
-    has_view_been_created = ViewEx::DoOnCreate(doc, flags);
-    if(!has_view_been_created)
+    if(!ViewEx::DoOnCreate(doc, flags))
         {
-        return has_view_been_created;
+        return false;
         }
 
     Run();
 
-    return has_view_been_created;
+    return true;
 }
 
 /// Place full illustration data on the clipboard as TSV.

mec_view.cpp

@@ -113,35 +113,22 @@ char const* mec_view::menubar_xrc_resource() const
 }
 
 /// Pop up an input dialog; iff it's not cancelled, create a view.
-///
-/// Trap exceptions to ensure that this function returns 'false' on
-/// failure, lest wx's doc-view framework create a zombie view. See:
-///   https://lists.nongnu.org/archive/html/lmi/2008-12/msg00017.html
 
 bool mec_view::OnCreate(wxDocument* doc, long int flags)
 {
-    bool has_view_been_created = false;
-    try
+    if(oe_mvc_dv_cancelled == edit_parameters())
         {
-        if(oe_mvc_dv_cancelled == edit_parameters())
-            {
-            return has_view_been_created;
-            }
-
-        has_view_been_created = ViewEx::DoOnCreate(doc, flags);
-        if(!has_view_been_created)
-            {
-            return has_view_been_created;
-            }
-
-        Run();
+        return false;
         }
-    catch(...)
+
+    if(!ViewEx::DoOnCreate(doc, flags))
         {
-        report_exception();
+        return false;
         }
 
-    return has_view_been_created;
+    Run();
+
+    return true;
 }
 
 wxPrintout* mec_view::OnCreatePrintout()