configure: silence error if tput not found

If tput is not found for colorizing, error message should be squashed.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

configure

@@ -418,7 +418,7 @@ EOF
 }
 
 quotes='""'
-if test -t 1 && which tput >/dev/null; then
+if test -t 1 && which tput >/dev/null 2>&1; then
     ncolors=$(tput colors)
     if test -n "$ncolors" && test $ncolors -ge 8; then
         bold_color=$(tput bold)