Revert "Change default log interval to 3 seconds for faster screen refreshes since vardiff will prevent massive on screen hash updates in the future."

This reverts commit f1f6b31faff2cca9a111407c28d4bf9af28284aa.

Screen update frequency is what I wanted to change, not the log interval.

cgminer.c

@@ -94,7 +94,7 @@ bool opt_realquiet;
 bool opt_loginput;
 bool opt_compact;
 const int opt_cutofftemp = 95;
-int opt_log_interval = 3;
+int opt_log_interval = 5;
 int opt_queue = 1;
 int opt_scantime = 60;
 int opt_expiry = 120;