Stops clearing sourcePaths during extraction.
Stops clearing sourcePaths during extraction.

The generator config document currently clears its set of source
filters while attempting to update that set. If the user quickly
saves a generator config while the extraction process is underway,
any existing sourcePaths will be discarded rather than left untouched.
This change simply stops removing the sourcePaths proactively and
allows them to be updated only when the info extraction completes.

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MOS_MIGRATED_REVID=120549088

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