Make bash shebangs through /usr/bin/env

This commit makes bash shebangs through /usr/bin/env. The originals work
correctly. However, it could be more flexible through /usr/bin/env. And
we already have a same thing in tools/tox_install.sh. So this commit
makes them consistent, too.

Change-Id: I35a6940cbd95c3b0f0d0f6391584b826e4de2ce5
2 files changed