Update sqrtx.py
Update sqrtx.py

error due to the wrong method name
kamyu104/LeetCode,tudennis/LeetCode---kamyu104-11-24-2015,kamyu104/LeetCode,tudennis/LeetCode---kamyu104-11-24-2015,tudennis/LeetCode---kamyu104-11-24-2015,kamyu104/LeetCode,kamyu104/LeetCode,kamyu104/LeetCode,tudennis/LeetCode---kamyu104-11-24-2015,tudennis/LeetCode---kamyu104-11-24-2015