Handle segfaults in clang-format vim-integration.
Handle segfaults in clang-format vim-integration.

A segfault used to clear the entire buffer. With this change, a message
to report a bug is displayed instead.

This should solve most cases similar to llvm.org/PR14774.

git-svn-id: a34e9779ed74578ad5922b3306b3d80a0c825546@171480 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra