Mutiple minor fix
- codelet/getrf: code indent
- descriptor: Fix memory leak on the name of the descriptor
- getenv: make sure the environment variable is cleand if needed
- starpu: Replace the getenv used to check the STARPU_DISK_SWAP_BACKEND
- starpu: Replace the getenv used to check the STARPU_SCHED value
- coreblas: replace unprotected getenv by chameleon_getenv