Fix warnings issued by clang:
Fix warnings issued by clang:

comparison of constant 18446744073709551615 with expression of type 'int' is always false [-Wtautological-constant-out-of-range-compare]

This was due to gutil originally being written for ints being unsigned by
default.

andrwng/kudu,EvilMcJerkface/kudu,helifu/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu,InspurUSA/kudu,cloudera/kudu,andrwng/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,InspurUSA/kudu,helifu/kudu,helifu/kudu,cloudera/kudu,cloudera/kudu,helifu/kudu,cloudera/kudu,helifu/kudu,andrwng/kudu,InspurUSA/kudu,InspurUSA/kudu,InspurUSA/kudu,InspurUSA/kudu,cloudera/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,andrwng/kudu,helifu/kudu,andrwng/kudu,cloudera/kudu,andrwng/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,helifu/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,helifu/kudu