6017 savecore's messages about read errors are useless

*** 264,275 ****
  
  static void
  Fread(void *buf, size_t size, FILE *f)
  {
          if (fread(buf, size, 1, f) != 1)
!                 logprint(SC_SL_ERR | SC_EXIT_ERR, "fread: ferror %d feof %d",
!                     ferror(f), feof(f));
  }
  
  static void
  Fwrite(void *buf, size_t size, FILE *f)
  {
--- 264,275 ----
  
  static void
  Fread(void *buf, size_t size, FILE *f)
  {
          if (fread(buf, size, 1, f) != 1)
!                 logprint(SC_SL_ERR | SC_EXIT_ERR, "fread: %s",
!                     strerror(errno));
  }
  
  static void
  Fwrite(void *buf, size_t size, FILE *f)
  {