Rename htools-hpc to hpc-tools to fix laziness

This is a stupid/trivial patch. I didn't realise when adding
htools-hpc that this will "break" tab completion on htools; as in, I
will have to add / manually always when completing files on the
command line.

So to fix my laziness, let's rename htools-hpc to hpc-htools,
eliminating this completion conflict.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>