libgit: increase timeout for autogit manager tests
libgit: increase timeout for autogit manager tests

These are pretty disk intensive and can lead to timeouts when CI
machines are loaded I think.

Hopefully future autogit optimizations will improve performance here.

keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/kbfs,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client