Put cbuildbot log file in chromite/buildbot no matter how its invoked
Put cbuildbot log file in chromite/buildbot no matter how its invoked

BUG=None
TEST=Ran cbuildbot from different places inside repo checkout

Change-Id: I4d23b66b4c27d9d0a7b7ed98937682d4fb17ed90
Reviewed-on: http://gerrit.chromium.org/gerrit/5221
Reviewed-by: Matt Tennant <46e612415b446ccde19638e4035892001c237942@chromium.org>
Tested-by: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>

coreos/chromite,zhang0137/chromite,coreos/chromite,coreos/chromite,bpsinc-native/src_third_party_chromite,zhang0137/chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,zhang0137/chromite