Fixed incorrect unsigned loop counter 	Loop in string::rfind works only because size_type is the same size 	as the pointer. When i is -1, it can be added to the pointer as 	unsigned, wraps around, and produces the correct index. If size_type 	were to change to a smaller type, this would stop working.
Fixed incorrect unsigned loop counter
	Loop in string::rfind works only because size_type is the same size
	as the pointer. When i is -1, it can be added to the pointer as
	unsigned, wraps around, and produces the correct index. If size_type
	were to change to a smaller type, this would stop working.

szastupov/ustl,PetteriAimonen/ustl,PetteriAimonen/ustl,szastupov/ustl,dgruss/ustl,Gerii/ustl,msharov/ustl,msharov/ustl,uusirant/ustl-cmake,NoSuchProcess/ustl,uusirant/ustl-cmake,NoSuchProcess/ustl,Gerii/ustl,dgruss/ustl,PetteriAimonen/ustl