Extra warnings when building with DEBUG and -O1

row0sel.cc:5483:8: warning: this statement may fall through
sp_head.cc:3355:14: note: 'sprintf' output between 37 and 55 bytes into a destination of size 17

Change-Id: Ibaf01a1ffde1191999273c843d6088082ccaa58d
(cherry picked from commit b046b9490b08116381a1d35e1815d7803a5169e2)