Fix clang warning "has virtual functions but non-virtual destructor".

Fix clang warning "has virtual functions but non-virtual destructor".

BUG= None
R=stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=fc707ffe812339bddf4ca28fbe8c01045e2b42d6

[Sean Klein, 2016-02-27 00:13:39]

Description was changed from

==========
Fix clang warning "has virtual functions but non-virtual descructor".

BUG= None
==========

to

==========
Fix clang warning "has virtual functions but non-virtual destructor".

BUG= None
==========

[Sean Klein, 2016-02-27 00:16:36]

smklein@chromium.org changed reviewers:
+ stichnot@chromium.org

[Jim Stichnoth, 2016-02-27 17:42:32]

lgtm

[Sean Klein, 2016-03-01 00:44:10]

Description was changed from

==========
Fix clang warning "has virtual functions but non-virtual destructor".

BUG= None
==========

to

==========
Fix clang warning "has virtual functions but non-virtual destructor".

BUG= None
R=stichnot@chromium.org

Committed:
https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a...
==========

[Sean Klein, 2016-03-01 00:44:11]

Committed patchset #1 (id:1) manually as
fc707ffe812339bddf4ca28fbe8c01045e2b42d6 (presubmit successful).