Don't crash out on OSErrors in subprocess calls

[asottile]

Resolves #1350

the output is a little non-ideal (repeated messages) but I can't think of a way to do this otherwise, looking at the shebang doesn't necessarily help (it could be an ELF binary, or a malformed ELF binary, or any other number of issues)

$ pre-commit run wat --all-files
wat......................................................................Failed
- hook id: wat
- exit code: 1

[Errno 8] Exec format error: '/home/asottile/workspace/pre-commit/t.sh'
[Errno 8] Exec format error: '/home/asottile/workspace/pre-commit/t.sh'