Bug 894147 - Follow-up: Remove leaky debugging code from BrowserElementParent.jsm.  r=me.

The second version of bug 894147 to land on b2g18 (after it was backed out once) already incorporates this fix.

--HG--
extra : transplant_source : %24i%997Po%92%0F%A5%10%97%94%5E%91%05X%F2%B7%15%20