Be more flexible about parsing parameters
Document IPv6 option
Fix allocate_find query.  Addresses #786
When clearing entries, set expiry time to now.  Addresses #786

This is so that the allocate_find will return the oldest IP.
And, the allocate_find will now use an index, rather than
potentially scanning the entire table
Remove "and expiry_time IS NULL".  Fixes #786

DHCP does multiple passes to allocate one IP.  We want to update
the allocated IP, no matter what it's previous state.

The allocate_find query takes care of allocating the correct IP.
We don't need to do extra checks in the allocate_update query
Update accounting queries to use NOW(), too.  Addresses #786
Added schema for DHCP IP pools.

With a key on Calling-Station-Id.
Order by callingstation-Id, too.  Fixes #786
Update huawei dictionary
Add a couple of attribute back
otp: Copy strings with explicit limiting

When copying username, challenge and password in otp_pw_valid, use
strlcpy accepting explicit destination size and verify its result,
instead of first assuming or verifying the string will fit and then
doing unlimited strcpy.

This silences the following Coverity errors.

Error: STRING_OVERFLOW (CWE-120):
freeradius-server-3.0.4rc2/src/modules/rlm_otp/otp_pw_valid.c:89: fixed_size_dest: You might overrun the 32 byte fixed-size string "otp_request.username" by copying "username" without checking the length.

Error: STRING_OVERFLOW (CWE-120):
freeradius-server-3.0.4rc2/src/modules/rlm_otp/otp_pw_valid.c:90: fixed_size_dest: You might overrun the 17 byte fixed-size string "otp_request.challenge" by copying "challenge" without checking the length.
freeradius-server-3.0.4rc2/src/modules/rlm_otp/otp_pw_valid.c:90: parameter_as_source: Note: This defect has an elevated risk because the source argument is a parameter of the current function.

Error: STRING_OVERFLOW (CWE-120):
freeradius-server-3.0.4rc2/src/modules/rlm_otp/otp_pw_valid.c:122: fixed_size_dest: You might overrun the 48 byte fixed-size string "otp_request.pwe.u.pap.passcode" by copying "rvp->data.strvalue" without checking the length.