Fix SELinux policy to allow chroot

Looks like SELinux additionally requires dav_override and
dac_read_search in order to be able to chroot. Additionally, we create
postsrsd_var_lib_t, which is what /var/lib/postsrsd should be instead of
the global var_lib_t.

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>

postsrsd.c: Close all file descriptors on process start.

Signed-off-by: Alexander GQ Gerasiov <gq@cs.msu.su>

Make hash length and hash minimum length configurable

Fixes #56

This reverts commit 9f971b2e66.

This addresses an issue mentioned in #55

Closes #49

New command line option to select listening interface

Fixes #48

add SELinux policy module

Closes #46

Fixes #45

Fixes #44

Fixes #33

The configuration file will never be overwritten automatically.
Therefore, changes need to be applied by the user manually.

Use char instead of char* for the single character and don't do this
weird casting thing where a char gets stored in the pointer.

Read config directly from environment variables

This reverts commit cdb223542a.

Network is not need anymore to start postsrsd.

Remove addrinfo flags

Remove flags since they require the network to be up and routable for no reason.

Closes #14
Closes #17

As reported in #25

Suggested by maxfieb (#21)

Fixes #21