Remove unused #include in chrome/common/variations/variations_util.cc.
Remove unused #include in chrome/common/variations/variations_util.cc.

Nothing from chrome/common/child_process_logging.h is used and thus
the #include is obsolete and can be removed.

BUG=None

Review URL: https://codereview.chromium.org/1294803002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#343394}

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