Fix warning to refer to Supplemental SSE3.

Impala executables use a Supplemental SSE3 instruction (see IMPALA-160), but the
warning message talks about SSE3, though the cpuinfo flag being checked is the right
one.  Let's fix this message and our internal flag names to avoid confusion.

Change-Id: Id00086bcd20c05eb9860a02b703d0455de689ea4
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/3973
Reviewed-by: Nong Li <nong@cloudera.com>
Tested-by: jenkins