Fix travis after_failure scripts
Fix travis after_failure scripts

It would print the following warning:

```
find: warning: Unix filenames usually don't contain slashes (though
pathnames do).  That means that '-name `ext/install.report'' will
probably evaluate to false all the time on this system.  You might find
the '-wholename' test more useful, or perhaps '-samefile'.
Alternatively, if you are using GNU grep, you could use 'find ...
-print0 | grep -FzZ `ext/install.report''.
```

Update the command to search in the `./ext` directory instead of the
root and search for the specific filename.

That way the contents do get printed if the file is found.

appsignal/appsignal-ruby,appsignal/appsignal,appsignal/appsignal-ruby,appsignal/appsignal,appsignal/appsignal-ruby,appsignal/appsignal-ruby