Fix pickling error in PackageBuildFailure.
Fix pickling error in PackageBuildFailure.

Right now, self.args in PackageBuildFailure has the wrong number of
arguments, because it relies on the parent object to populate
self.args, and the parent has different arguments. Declare self.args
explicitly instead.

BUG=chromium:313385
TEST=cbuildbot run with rspangler's change

Change-Id: I025da3c6d55ed4371b5f0afa9a40d0e9ecf07304
Reviewed-on: https://chromium-review.googlesource.com/175170
Reviewed-by: Matt Tennant <46e612415b446ccde19638e4035892001c237942@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite