This avoids warnings about an empty body in an if statement.
mem_free does the same null check, so the accidental extra
semicolon was harmless, and the whole if statement actually
is needless. But if removing the if statements, all the
other ones should be removed too, for consistency.
(This could be done as a separate change).
Change-Id: I1b6064dedd15ffa949043bb5396148aaed9b43f6
a9e1747f9e