[packages] fix nmap build variants (#9387)

The default variant of nmap does not appear to be building correctly, if
at all (all invocations of configure have --with-openssl).  Add a nossl
variant to fix building.

Set PKG_BULID_DIR to differ between variants to prevent overlapping of
builds.

Signed-off-by: Kevin Locke <klocke@digitalenginesoftware.com>
SVN-Revision: 26951