Fix some user-reported bugs

Fix some user-reported bugs

Testing : precheckin --full --strict-errors
Reviewer: Sergey V, Shaun M

JTB impact: No
Ops impact: No

Change to config                        : No
Change to XML schema                    : No
Change to DB schema                     : No
Change to transport (timeouts, headers) : No
Any change (or new use) of OAQs         : No
Change to inter-component transactions  : No
Depends on any other checkin / bug      : No

Tests that will verify:

The CL-Protobufs tests

Description:

I had made a "policy decision" that the package created
by importing a .proto file would (:use :common-lisp). In
practice, this turned out to be a mistake. Sergey suggested
a fix that I think is correct, so in it goes.

Shaun noticed that the optimized 'serialize-object' and
'object-size' methods didn't quite implement what they were
supposed to for optional boolean fields whose value was never
supplied. Fix the optimized methods to implement the same
(correct) semantics as the unoptimized ones.

git-svn-id: http://svn.internal.itasoftware.com/svn/ita/trunk/qres/lisp/libs/cl-protobufs@561714 f8382938-511b-0410-9cdd-bb47b084005c