All the frameworks are ported now, so this is no longer necessary.
Checked by building everything with kdesrc-build.

Overriding a CMake package like this will just cause all sorts of
headaches later on.  In this particular case, projects that depended on
CMake 2.8.13 or later (more likely 3.0.0) would fail with a message
about removing the CMakePackageConfigHelpers file, but would have no way
to do that while still using ECM.

This also renames the configure_package_config_file() macro to
ecm_configure_package_config_file(), so that anything including
CMakePackageConfigHelpers afterwards does not overwrite the macro
unexpectedly.

For now, we keep a CMakePackageConfigHelpers.cmake file that just wraps
ecm_configure_package_config_file() as configure_package_config_file()
to keep the frameworks building while they are ported.

REVIEW: 115496
Reviewed by Sune Vuorela <kde@pusling.com>

Add a macro for finding dependencies. It should be in a future
version of CMake. Finding dependencies is one of the major missing
pieces of KF5 Config files.