Small memory allocation issue reporting

[bygo7]

I found it during using the fuzzing_session.

hammer-suite.c
...
char *hPatt_2_str(HammerPattern * h_patt, int fields)
{
static char patt_str[256];
char *dAddr_str;
memset(patt_str, 0x00, 256);
...

If randomly generated aggressor numbers become big, the memory allocated for patt_str(256 bytes) becomes a problem, leading to a segmentation fault.
In my case, 22-row aggressors made the error, and changing 256 to 1024 has solved the problem.