We use the mtime on the network profile as the 'Last Connected Time'.
When we update any property and sync the file to disk, the mtime was not
preserved (since we were creating a new temporary file instead of
modifying the old one). This led to LastConnectedTime property change
being emitted / updated incorrectly when a writable property on the
KnownNetwork interface was updated.
create_dirs was dependent on the path ending in '/' to create the
full path. The hotspot code did not include a '/' at the end so
it was not getting created, which prevented the hotspot module
from initializing.
Make the network_storage_* functions uniformly accept an enum value
instead of a string so that he conversion to string doesn't need to
happen in all callers.
network_settings_load expects NULL value to be returned
on failed attempts to read the settings files inside of
storage_network_open. At the same time storage_network_open
used to always return an initialized l_settings
structure despite the outcome of the read operations,
indicating a success.
