Two variables named 'result' were defined, at the outer level a
UBYTE to hold the function return value and the inner a COUNT to
hold returns from 'truename()'. The overall function return value
was always FCB_SUCCESS due to shadowing, however removing the
inner variable definition as a fix does not work due to sign
issues and intermixing of the variable uses, so rename the inner
variable.
Tested this patch using FDPP platform
1/ Simple rename of file with conditions for success (ok)
2/ Simple rename of file with conditions for failure - source missing (ok)
3/ Simple rename of file with conditions for failure - target exists (ok)
Fixes#16
