Align tested boolean/Boolean expectations

Align tested boolean/Boolean expectations

This patch removes implicit boxing/unboxing by aligning boolean/Boolean
expectations.

Future<Boolean>.get() will return a Boolean, hence use assertEquals() for
these (and Optional<Boolean>). Doing that instead of assertTrue()/assertFalse()
eliminates a single Eclipse info-level message about Boolean being unboxes.
This also has better behavior: if the tested method returns null, we'll get
an assertion failure instead of a NPE.

For isPersent() and other methods which return a boolean, use assertTrue()
or assertFalse(). Doing that instead of assertEquals() eliminates two Eclipse
info-level messages about boxing the two arguments to Boolean, for some
reason there is no assertEquals(boolean, boolean).

Change-Id: If86ef9fb1ecf4cdceb45bc079bba1a86cff311ac
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>