Various make dist/clean/distclean fixes. No code changes.

Various make dist/clean/distclean fixes. No code changes.

- Workaround for src ../test-suite/test_tools.cc dependency crashing
  make distclean. Automatically copy the file to src to compile.
- "make dist" fixes to not include generated files. Mainly involves
  moving them to a suitable nodist_..._SOURCES variable.
- "make clean" fixes to remove generated files
- Always recurse configure into sub-projects. make dist fails othewise.
- Removed fatal error from squid_kerb_auth configure if no kerberos
  lib found (also a fatal error at build time)