Update the handling of the native bridge property.

ro.dalvik.vm.native.bridge is expected to be always be set. A value of
"0" means that the native bridge is disabled and that no value should be
passed to the runtime.

Bug: 17104449

(cherry picked from commit 831bd75b2bbc126f02578a967e925271b9cac6d3)

Change-Id: Ib483ac8e96bdc66af2725815807d4deb36fb36ab