Build fail wiith a statement that may fall through

[pgulutzan]

I have Ubuntu 18.04 and Tarantool 2.0, pulled from source today.
The gcc version is 7.3.0, and there have been changes affecting switches
https://developers.redhat.com/blog/2017/03/10/wimplicit-fallthrough-in-gcc-7/

When I use default cmake and make I see:
[ 34%] Building C object src/box/sql/CMakeFiles/sql.dir/insert.c.o
/home/pgulutzan/tarantool-2.0/src/box/sql/insert.c: In function ‘vdbe_emit_constraint_checks’:
/home/pgulutzan/tarantool-2.0/src/box/sql/insert.c:893:4: error: this statement may fall through [-Werror=implicit-fallthrough=]
sqlite3MayAbort(parse_context);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/pgulutzan/tarantool-2.0/src/box/sql/insert.c:894:3: note: here
case ON_CONFLICT_ACTION_ROLLBACK:
^~~~
cc1: all warnings being treated as errors
src/box/sql/CMakeFiles/sql.dir/build.make:446: recipe for target 'src/box/sql/CMakeFiles/sql.dir/insert.c.o' failed
make[2]: *** [src/box/sql/CMakeFiles/sql.dir/insert.c.o] Error 1