Store size from volatile sources for already installed versions

Volatile sources are parsed after the status file, so if we have a
version already installed the size information is not stored, so that
a reinstall of said version is refused claiming a broken repository.

References: 1412cf5140

apt-pkg/deb/deblistparser.cc

@@ -404,8 +404,13 @@ uint32_t debListParser::VersionHash()
             half-configured, triggers-awaited, triggers-pending, installed
  */
 bool debListParser::ParseStatus(pkgCache::PkgIterator &,
-				pkgCache::VerIterator &)
+				pkgCache::VerIterator &Ver)
 {
+   // the status file has no info about the download size and
+   // usually this is fine as we will have picked that info up already –
+   // except if we have volatile sources which are parsed after the status file.
+   if (Ver->Size == 0)
+      Ver->Size = Section.FindULL(pkgTagSection::Key::Size);
    return true;
 }
 bool debStatusListParser::ParseStatus(pkgCache::PkgIterator &Pkg,

test/integration/test-apt-get-install-deb

@@ -7,6 +7,9 @@ TESTDIR="$(readlink -f "$(dirname "$0")")"
 setupenvironment
 configarchitecture 'amd64' 'i386'
 
+# XXX: Remove temporary hack
+rm rootdir/etc/apt/apt.conf.d/temporary-allow-unsized-packages
+
 # regression test for #754904
 cat > foo.rpm <<EOF
 I'm not a deb, I'm a teapot.