Check if socket has not been closed after timeout in read

discussed on jabber

this workaround should avoid this build error:
http://git.bind10.isc.org/~tester/builder//BIND10/20120903130000-FreeBSD8-i386-Clang/logs/build.out

fix my previous commit; sorry I tested wrong. This changes
+= to just = for first use of MAINTAINERCLEANFILES.

Use "make maintainer-clean" instead of "make distclean" to remove the manpages.
This fixes problem where enduser using tarball does a "make clean"
and loses the maintainer-tarball-provided manpages.

Fix a misspelling in a log output.
Also fix same misspelling in some comments and unittest output.

This has not been reviewed. Let's consider it a stub for now.

removed the conflicting generated files

The tests didn't fail due to missing file. See memory_datasrc_unittest.cc:

EXPECT_THROW(zone_finder_.load(TEST_DATA_DIR "/duplicate_rrset.zone"),
...
EXPECT_THROW(rootzone.load(TEST_DATA_DIR "/duplicate_rrset.zone"),

I assume this is a false-negative because the test successds because
loading still fails.

Maybe that test or "load" should be extended for this, but for now I add
the missing file to EXTRA_DIST.

detected by distcheck failure:
http://git.bind10.isc.org/~tester/builder/BIND10-distcheck/20120831093000-FreeBSD8-i386/logs/distcheck.out

discussed on jabber

- explain 0 value for tcp_recv_timeout
- initialize value in config parser (to 0, it will be set by build() anyway)

b10-loadzone tries to remove comments from RData strings

It will simplify various parts of the code.
Name object is expensive, but either way it involves memory allocation
anyway, so performance impact wouldn't be much different.

they are basically false positives, but addressing them is not difficult
so I modified the code rather than suppressing them.

okayed on jabber.