find_dependency: Don't propagate EXACT argument.

If a package is requested with an EXACT version, that doesn't imply
that dependencies must be found EXACTly too.

Extend the macro to allow specifying that a dependency must be found
by EXACT version instead.
Merge topic 'fix-find_dependency-EXACT' into next

08ba128f find_dependency: Don't propagate EXACT argument.
find_dependency: Extend the tests for use of EXACT macro parameter.
Merge topic 'fix-find_dependency-EXACT-for-master' into next

45abfb0c find_dependency: Extend the tests for use of EXACT macro parameter.