fix sscanf %qd type mismatch warning
fix sscanf %qd type mismatch warning

Fixes this warning:

    relative_time.cc: In member function ‘bool relative_time::parse(const char*, size_t, relative_time::parse_error&)’:
    relative_time.cc:222:62: warning: format ‘%qd’ expects argument of type ‘long long int*’, but argument 3 has type ‘int64_t* {aka long int*}’ [-Wformat=]
                         if (sscanf(numstr.c_str(), "%qd", &number) != 1) {
                                                                  ^

tstack/lnav,tstack/lnav,sureshsundriyal/lnav,tstack/lnav,sureshsundriyal/lnav,sureshsundriyal/lnav,tstack/lnav,sureshsundriyal/lnav