Files in $element/environment.d are meant to be sourced, so drop
the executable bit. Moreover, drop the executable bit from a couple
of other scripts that are either meant to be sourced or simply because
they are configuration files.
Change-Id: I7f724dd9d409f4a835a136f12f48a84aa9acc41e
For some use cases, it can be useful to keep all the kernels
and not just keep the latest one. Add a parameter that allows
it, and continue cleaning up kernels by default.
Change-Id: Ia6e6c1fa18e3724c1eb89226151d81e9e748b793
