Fix bad JACK_PLUGIN variable

Changed to LOCAL_JACK_PLUGIN.

(cherry picked from commit 17924b136cb5bfc60d138e8c7e5c18a90b5965c3)

Test: Manually tested by some manual activations of the coverage plugin.
Change-Id: I1be4aaa502103fc308d35a5672dc4fe5900c4ebe
3 files changed