When running brew -v install, long post_install output from the formula,
presumably from upstream, may hide the important instructions in the
caveats and confuse the user. For example, postgresql runs initdb which
prints its own instructions for running the database, making the caveats
scroll off screen.

Per xu-cheng's instructions in Homebrew/homebrew#42565 :

Remove the explicit call to caveats from the install, reinstall, and
upgrade commands, as well as the dependency installer code in
FormulaInstaller#install_dependency , and call caveats right before the
summary code in FormulaInstaller#finish .

Closes Homebrew/homebrew#42565.

Signed-off-by: Xu Cheng <xucheng@me.com>