The paging control can cause issues on servers that put limits on
how many paging controls can be active at one time (on some
servers, it is limited to one per connection). We need to reduce
our usage so that we only activate the paging control when making
a request that may return an arbitrary number of results.

https://fedorahosted.org/sssd/ticket/1202 phase one

This is mostly a cosmetic patch.

The purpose of wrapping a multi-line macro in a do { } while(0) is to
make the macro usable as a regular statement, not a compound statement.

When the while(0) is terminated with a semicolon, the do { } while(0);
block becomes a compound statement again.