Does not handle thrift files with flow-protected keywords as the file name

[boconnell]

Problem:
For example, if a file foo.thrift imports the file any.thrift and tries to references one of any.thrifts exports, the generated flow code will ultimately look like:

foo.js:

import any from './any';

type bar = {
  a: any.baz,
}

at which point flow will report an error because it doesn't expect a . after the keyword any. I imagine this might happen with other file names that are flow-protected keywords.