buildozer: make ellipsis work with BUILD.bazel and BUCK files

[swolchok]

Fixes #91.

Regarding CLA, this contribution is being made on behalf of my employer, Facebook.

[bazel-io]

Can one of the admins verify this patch?

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[pmbethe09]

the problem with this change is the intentionally random iteration order of Go maps.

You probably need to keep the list for this part and the map for below

[swolchok]

good catch, I forgot that the iteration order mattered.

[swolchok]

should be fixed!

[pmbethe09]

Jenkins, test this please.

[pmbethe09]

LGTM, just waiting for CI