Remove skydb dependency on build/android/pylib

Remove skydb dependency on build/android/pylib

I also fixed skydb to use --args-for sky_debugger to
automatically issue the load from 'start' even when
the --gdb option is present.

I tried to invoke gdb_attach directly from within start_command
but that seemed to cause some strangeness with my zsh shell
where it would automatically suspend gdb.  So I'll revisit
that change in the next patch.

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/8feb05cdaa77caa096e89b473c8a582582621b23

[abarth-chromium, 2015-01-27 23:56:09]

lgtm

[eseidel, 2015-01-27 23:56:27]

Committed patchset #1 (id:1) manually as
8feb05cdaa77caa096e89b473c8a582582621b23 (presubmit successful).