[glade--]Buggy #include filenames.

The _glade files get the wrong include name sometimes.
It seems to be in the case where a widget has the separate class 
attribute set, and the .h file is already existing.

How to reproduce:

1. Create a C++ project file including these widgets:

<widget>
   <class>GtkWindow</class>
   <name>window1</name>
   <title>window1</title>

   <widget>
     <class>GtkButton</class>
     <cxx_separate_class>True</cxx_separate_class>
     <cxx_separate_file>True</cxx_separate_file>
     <name>button1</name>
   </widget>
</widget>

2. Run glade--:  glade-- proj1.glade

3. Check the output:   grep _new src/window1_glade.hh
    This should not return anything.

4. Create a button1.hh file in the current directory: touch button1.hh

5. Run glade--:  glade-- proj1.glade

6. Check the output:   grep _new src/window1_glade.hh
    Output is obviously wrong: #include "button1.hh_new"


The patch is created with: diff -u Class.cc.~1.11~ Class.cc
I'm not sure which format is common for submitting patches.
Since the tests woüldn't compile (perhaps because of me having old 
automake/conf stuff), I'm not sure if this patch has any side-effects.


-- 
Audun H. Ellertsen, Software engineer   http://www.procaptura.com
proCaptura A/S                          Tel work : +47 66 85 51 00
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