wkhtmltopdf: fix current working directory issue

As wkhtmltopdf sometimes needs to get files in
current working directory ONLY, this has to be
set correctly.

E.g. `wkhtmltopdf toc --xsl-style-sheet no_absolute_path.xsl input.html output.pdf`

component/wkhtmltopdf/buildout.cfg

@@ -33,7 +33,6 @@ script =
   wrapper_location = os.path.join("%(location)s", "wkhtmltopdf")
   wrapper = open(wrapper_location, 'w')
   wrapper.write("""#!${dash:location}/bin/dash
-  cd %(location)s
   export LD_LIBRARY_PATH=%(location)s:${libXrender:location}/lib/:${fontconfig:location}/lib/:${libX11:location}/lib/:${libXext:location}/lib/
   export PATH=${fontconfig:location}/bin:$PATH
   exec %(location)s/wkhtmltopdf-""" + WK_SUFIX_MAP[platform]+ """ $*""")