Revert "[Jenkins] auto-formatting by clang-format version 6.0.0 (tags/google/stable/2017-11-14)"
Revert "[Jenkins] auto-formatting by clang-format version 6.0.0 (tags/google/stable/2017-11-14)"

This reverts commit 875a6576cc824fc9c4eb52597633aeb2cccff6ba.

stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math