[swig] Start of pylint on python build scripts.

Summary:
This does a broad first pass on cleaning up a lot of the noise when
using pylint on these scripts. It mostly addresses issues of:

* Mixed tabs and spaces.
* Trailing whitespace.
* Semicolons where they aren't needed.
* Incorrect whitespace around () and [].
* Superfluous parentheses.

There will be subsequent patches with further changes that build
upon these.

Reviewers: zturner, domipheus

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D14375

llvm-svn: 252244