NO-JIRA: Fix problem with config.h.in introduced by recent commit.

- Separate config.h.in for router and src subdirs, only define what is needed for each.
- Remove src/ from include_directories for router subdir, not needed, shouldn't be used.
- Remove unused conditionals.h.in

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1646276 13f79535-47bb-0310-9956-ffa450edef68