[PATCH] get_home_path: use HOME

Hi,

I work in an environment, where servers are administered by people
with different user names and identical uid (0). The attached patch
fixes a bug exposed in such environments: where the logic of
retrieving a personal configuration file relies solely on
get_home_path(), the different users are forced to share the file of
the first user with given uid.

The usage of HOME environment variable (if set) is IMO the right,
standard and faster way to get_home_path().

r.