You can now (as of version 0.6) use :exclude-members: to exclude specific members from the documentation:
The directives supporting member documentation also have a
exclude-members option that can be used to exclude single member names
from documentation, if all members are to be documented.New in version 0.6.
Source: http://www.sphinx-doc.org/en/stable/ext/autodoc.html
In your specific case, you would add :exclude-members: log into your .rst file.