Buck: Upgrade to the latest version

The reason for upgrade is recently implemented feature: [1] to remove
output directory when switching between Buck versions. The structure
of the output directory can change between Buck versions, so this is
always needed step anyway.

[1] https://github.com/facebook/buck/commit/7e153d4a69044d059288d353fc1a442e07cbea58

Change-Id: Icd42a2114949f68d2f9a38d49bd77681a2f088ac