do not modify DepIterator as we might check again

fixup for 42d51f333e8ef522fed02cdfc48663488d56c3a3

The for-loop iterating over the DepIterators which need configuration
can (and will be in 'complicated' situations) run multiple times, so we
can't just GlobOr on the DepIterator as it modifies it, so that the next
iteration over the list ends up checking another dependency leading us
into a 'Internal error, packages left unconfigured. foopkg' maybe or we
are 'lucky' and calculate a solution which might break down the line

Git-Dch: Ignore
fix SHA2* cleanups to zero-out the complete context

GCC 4.8 is now clever enough to warn about:

contrib/sha2_internal.cc: In function ‘char* SHA256_End(SHA256_CTX*, char*)’:
contrib/sha2_internal.cc:656:31: warning: argument to ‘sizeof’ in ‘void*
memset(void*, int, size_t)’ call is the same expression as the destination;
did you mean to dereference it? [-Wsizeof-pointer-memaccess]
   MEMSET_BZERO(context, sizeof(context));

So fix it as suggested. Its interesting though that the SHA2*
calculation as far as we need it works even without zeroing out.

Git-Dch: Ignore
delete Memb on read-error in arfile

Git-Dch: Ignore
simple fork and pidfile aptwebserver

Forking only after being ready to accept clients avoids running races
with the tests which sometimes failed on the first 'apt-get update'
(or similar) with the previous background-start and hope for the best…

The commit fixes also some oversight output-order changes in regards to
Description-md5 and (I-M-S) race conditions in various tests.

Git-Dch: Ignore