Removed inquiry_adf_need_mirror_rear variable

After fixing the duplexer initialization, it became clear that the code was
mirroring the back pages.  Since the scanner already supports page
mirroring internally with an optional bit setting (which was already set)
it made the most sense to simplify the code base and remove the variable.

backend/avision.c

@@ -3204,7 +3204,6 @@ get_accessories_info (Avision_Scanner* s)
     {
       dev->inquiry_duplex = 1;
       dev->inquiry_duplex_interlaced = 0;
-      dev->inquiry_adf_need_mirror_rear = 1;
     } else if (result[0] == 0 && result[2] != 0) {
       /* Sometimes the scanner will report that there is no ADF attached, yet
        * an ADF model number will still be reported.  This happens on the
@@ -7081,8 +7080,7 @@ reader_process (void *data)
       /* FURTHER POST-PROCESSING ON THE FINAL OUTPUT DATA */
       
       /* maybe mirroring in ADF mode */
-      if ((s->source_mode_dim == AV_ADF_DIM && dev->inquiry_adf_need_mirror) ||
-	  (s->source_mode == AV_ADF_DUPLEX && dev->inquiry_adf_need_mirror_rear && s->page % 2 == 0))
+      if (s->source_mode_dim == AV_ADF_DIM && dev->inquiry_adf_need_mirror)
         {
 	  if ( (s->c_mode != AV_TRUECOLOR) ||
 	       (s->c_mode == AV_TRUECOLOR && dev->inquiry_adf_bgr_order) )

backend/avision.h

@@ -368,7 +368,6 @@ typedef struct Avision_Device
   SANE_Bool inquiry_needs_software_colorpack;
   SANE_Bool inquiry_needs_line_pack;
   SANE_Bool inquiry_adf_need_mirror;
-  SANE_Bool inquiry_adf_need_mirror_rear;
   SANE_Bool inquiry_adf_bgr_order;
   SANE_Bool inquiry_light_detect;
   SANE_Bool inquiry_light_control;