net: don't preserve 1xx responses in parser buffer.

      It's unclear why 1xx responses were kept in the parser's buffer previously so
this change aligns their processing with all other response types.

BUG=299892

Review URL: https://codereview.chromium.org/25312002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226539 0039d316-1c4b-4281-b951-d872f2087c98