AA: openssl: Support multi-threaded applications

(This is a backport of r39048 from trunk).

Allow multi-threaded applications to work properly by
removing the "no-threads" flag that is enabled by default.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>

git-svn-id: svn://svn.openwrt.org/openwrt/branches/attitude_adjustment@39585 3c298f89-4303-0410-b956-a3cf2f4a3e73