subsurface: add dependency on gconf
* fails without
| Package gconf-2.0 was not found in the pkg-config search path.
| Perhaps you should add the directory containing `gconf-2.0.pc'
| to the PKG_CONFIG_PATH environment variable
| No package 'gconf-2.0' found
| main.c:7:32: fatal error: gconf/gconf-client.h: No such file or directory
| #include <gconf/gconf-client.h>
(From meta-openembedded rev:
331d0a98ce13280d1e14b8db9e582a582977d1fb)
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>