Introduces a new option --debug-to-files which makes SSSD output its
debug information to a file instead of stderr, which is still the
default.

Also introduces a new confdb option debug_to_files which does the same,
but can be specified per-service in the config file.

The logfiles are stored in /var/log/sssd by default.

Changes the initscript to log to files by default.

This converts a great many configuration options to the new
standard format.

This reverts commit 8c50bd085c0efe5fde354deee2c8118887aae29d.

Amended: commit 1016af2b1b97ad4290ccce8fa462cc7e3c191b2e also made
use of the SYSLOG_ERROR() macro, so those portions of that code
also needed to be reverted.

This is just a band-aid until ELAPI is fully functional and ready to
use.

Implement a set of python bindings for the sysdb with feature set
similar to what is available in the tools. The primary
consumers would be applications like system-config-users.

Resolves: Ticket #102

Fixes: #138

Because the confdb always operates synchronously, it maintains its
own private event context internally. The event context argument
passed to it is never used, so we'll remove it to avoid confusion.

- older version of libpcre only support the Python syntax (?P<name>)
  for named subpatterns

The special persistent local database retains the original name.
All other backends now have their own cache-NAME.ldb file.