Fix cupsRasterReadHeader regression.

Report I/O errors.

Finish migration of testraster to test-internal.h.

Author: michaelrsweet

cups/raster-stream.c

@@ -847,7 +847,7 @@ cupsRasterReadHeader(
 
   memcpy(h, &r->header, sizeof(cups_page_header_t));
 
-  return (0);
+  return (1);
 }
 
 
@@ -1394,9 +1394,12 @@ cups_raster_io(cups_raster_t *r,	// I - Raster stream
 
     DEBUG_printf("6cups_raster_io: count=%d, total=%d", (int)count, (int)total);
     if (count == 0)
+    {
       break;
+    }
     else if (count < 0)
     {
+      _cupsRasterAddError("I/O error");
       DEBUG_puts("6cups_raster_io: Returning -1 on error.");
       return (-1);
     }