configure.ac: when checking g_checksum_new() use the proper Glib library path
configure.ac: when checking g_checksum_new() use the proper Glib library path

Since this would test against the system glib, even if we're using
a private copy.

Signed-off-by: Balazs Scheidler <c9ced0bffa833fad400e0759f75a89a845bcc267@balabit.hu>

algernon/libmongo-client,algernon/libmongo-client,algernon/libmongo-client