Require --force to link keg-only.

Closes #13349.
Only check keg-only if we map to a formula
git-tf: fix exec script

Fixes #17411.
FormulaInstaller: actually select unsatisfied requirements

Fixes #17422.
h5utils 1.12.1

Closes #17378.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>