[#256] Fix exception message
[#256] Fix exception message

* Typo: Scrol -> Scroll
* We need to format the string with the args ourselves (ScanError won't
  do it).
  Otherwise the args in the ScanError won't be substituted.

brunobell/elasticsearch-py,elastic/elasticsearch-py,elastic/elasticsearch-py,Garrett-R/elasticsearch-py,brunobell/elasticsearch-py