[RFA] Remove most cleanups from linux-thread-db.c

[Simon Marchi]

On 2018-02-22 12:02, Tom Tromey wrote:
> The remaining cleanup in linux-thread-db.c uses
> make_cleanup_free_char_ptr_vec, which requires a somewhat bigger
> change.

I had a patch for that lying around, so I posted it along with other 
cleanup patches to get rid of free_char_ptr_vec here, if you want to 
take a look:

https://sourceware.org/ml/gdb-patches/2018-02/msg00355.html

Simon