Use jsgf folder for jsgf imports search path.

Fixes issue https://sourceforge.net/p/cmusphinx/bugs/406/

Thanks to Laimis



git-svn-id: svn+ssh://svn.code.sf.net/p/cmusphinx/code/trunk/sphinxbase@12711 94700074-3cef-4d97-a70e-9c8c206c02f5