Relocate teuthology checkouts to ~/src/

Also use an underscore instead of a dash between 'teuthology' and the
branch name.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Don't mess with ~/src/teuthology by default

Setting 'automated_scheduling: True' in ~/.teuthology.yaml enables it.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>