eglibc: Avoid "installed but not shipped" warning for ld.so.conf

eglibc: Avoid "installed but not shipped" warning for ld.so.conf

If USE_LDCONFIG is not set then we won't ship ld.so.conf.  However,
eglibc still installs it which leads to a QA warning.  Prevent that by
removing the file (and the subsequently-empty directory /etc) in this
situation.

(From OE-Core rev: 23b5dd2ab8a556fcef3aa34689310d9d5f61b3d1)

Signed-off-by: Phil Blundell <philb@gnu.org>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>