Correct test to use Unsigned version of function

Jan Breuer

2015-10-04 4133f2d8ba0d49c6d9a6a93650a81743aef81fa4

 libscpi/src/units.c

@@ -38,6 +38,7 @@
#include "scpi/parser.h"
#include "scpi/units.h"
#include "utils_private.h"
#include "scpi/utils.h"
#include "scpi/error.h"
#include "lexer_private.h"