Added old IDF back for historical runs. refs #8009

Code/Mantid/instrument/BASIS_Definition.xml

 <?xml version='1.0' encoding='ASCII'?>
-<instrument valid-to="2100-01-31 23:59:59" name="BASIS" valid-from="1900-08-02 16:09:00">
+<instrument valid-to="2100-01-31 23:59:59" name="BASIS" valid-from="2013-07-19 00:00:00">
   <!-- Created by Stuart Campbell -->
   <defaults>
     <length unit="metre"/>