Make kpackage_install_package work with KDE_INSTALL_DIRS_NO_DEPRECATED

Summary:
Currently kpackage_install_package fails if KDE_INSTALL_DIRS_NO_DEPRECATED
is set to TRUE, because the macro is still using the deprecated var
DATA_INSTALL_DIR
It should be fine to bump the min version of ECM required to needed ECM 1.6.0,
as someone using KF5 5.27 very surely also has a similar recent ECM.

Reviewed By: mart

Differential Revision: https://phabricator.kde.org/D2726