Rather fail with ResourceNotFoundException.
This is e.g. important for the GetDiff REST endpoint as it returns an
empty diff for non-existing files. As result the diff screen shows an
empty diff for any non-existing file, but users expect to see an
error.
This change may break existing users of the extension API since the
RevisionApi#file(String) is now throwing RestApiException.
Change-Id: If0c172818b553129145f5ccd2f99e19b94472cce
Signed-off-by: Edwin Kempin <ekempin@google.com>
0520e08cb6