Integration tests mangles Unicode quotes

GHC output some curlies and they got mangled by the test suite:

```
ezyang@sabre:~/Dev/cabal-tmp/cabal-install$ ../dist-newstyle/build/cabal-install-1.25.0.0/build/integration-tests/integration-tests -p monitor_cabal_files
Integration Tests
new-build
monitor_cabal_files.sh (ignoring stdout+stderr): FAIL (10.46s)
Unexpected exit status.

Exit status: ExitFailure 1
Working directory: /tmp/cabal-install-test-19717

was:
Resolving dependencies...
In order, the following will be built (use -v for more details):
q-0.1.0.0
Configuring q-0.1.0.0...
Preprocessing executable 'q' for q-0.1.0.0...

was:

Main.hs:2:8:
Could not find module âPâ
Use -v to see a list of the files searched for.
```

CC @BardurArantsson