In commit v3.2.0-rc1~480^2 (QtAutogen: Regenerate qrc files if their input
changes, 2014-09-17) the "cmake -E cmake_autogen" rule was switched from
always running to running as a custom command with dependencies if rcc
is enabled. This is not correct because automoc always needs to re-run.
Switch back to always running the command.
Brad King