Ninja: Avoid re-running CMake on next build after regeneration

In commit 4a6397a7 (Ninja: Track configured files so we can regenerate
them, 2013-06-17) we accidentally started listing files generated by
CMake as inputs to the configuration process instead of outputs from it.
Move the list of files generated by CMake to the regeneration rule
outputs section and tell Ninja to restat after running it.
Merge topic 'ninja_fix_rerun'

6fac24d7 Ninja: Avoid re-running CMake on next build after regeneration