BUG/MINOR: sample: Set the correct type when a binary is converted to a string

A binary sample data can be converted, implicitly or not, to a string by cutting
the buffer on the first null byte.

I guess this patch should be backported to all stable versions.

src/sample.c

@@ -623,6 +623,7 @@ static int c_bin2str(struct sample *smp)
 			break;
 		}
 	}
+	smp->data.type = SMP_T_STR;
 	return 1;
 }