Touch output files before reading or writing them, so that they are

Touch output files before reading or writing them, so that they are
always guaranteed to exist. This fixes PR444. Thanks to Alkis
for reporting the bug and testing the patch.
AddRecord used to return a big list, but that return value was never
used. So now it doesn't return anything.
Create the WebDir if it does not exist.
Fix a typo in a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16541 91177308-0d34-0410-b5e6-96231b3b80d8