sourceMappingURL matcher should stop on a non-matching non-blank line

[waltjones]

The matcher in parseMapPath should stop when it encounters a non-blank, non-matching line, else it may match the string that belongs to a concatenated file. This will only occur in files that don't have a valid sourceMappingUrl, and will result in a false match

https://github.com/rollbar/rollbar-cli/blob/master/src/sourcemaps/scanner.js#L179