If we fail to create a temporary file for the precompiled preamble,

just abort creation of the precompiled preamble rather than doing
silly things. This is the second part of the fix for the weird
preamble-related failures on Windows. Big thanks to Francois Pichet
for the great detective work!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113697 91177308-0d34-0410-b5e6-96231b3b80d8