Allow full data path to be given with folders having dots

The issue of the system test was related that the ubuntu and mac os path name
had a folder with a dot. And the input was expecting only a file_name'.'extension.

Now, if it finds more than one dot, it will get only the last one to split
the file - extension.

re #7221

Code/Mantid/scripts/SANS/isis_reduction_steps.py

@@ -301,6 +301,11 @@ def _extract_run_details(self, run_string, is_trans=False, prefix='', run_number
             @param run_number_width: ISIS instruments often produce files with a fixed number of digits padded with zeros
         """
         pieces = run_string.split('.')
+        if len(pieces) > 2: 
+            # this means that the foldername has '.',  so costruct the pieces to ignore foldername with '.' 
+            extension = pieces[-1]
+            body = '.'.join(pieces[:-1])
+            pieces = [body, extension]
         if len(pieces) != 2:
              raise RuntimeError, "Invalid run specified: " + run_string + ". Please use RUNNUMBER.EXT format"