[simple-scan] Remove ADF front source which was accidently added in commit a3639abcd563ac34f91ea72659abd5055a80e11

[Bartosz <bkosiorek src gnome org>]

commit 907940acaa50b370654808ee6dcf01dbefe81e62
Author: Bartosz Kosiorek <gang65 poczta onet pl>
Date:   Sat Mar 28 23:49:44 2020 +0100

    Remove ADF front source which was accidently added in commit a3639abcd563ac34f91ea72659abd5055a80e11b

 src/scanner.vala | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/src/scanner.vala b/src/scanner.vala
index 0bef3e3..75474af 100644
--- a/src/scanner.vala
+++ b/src/scanner.vala
@@ -932,7 +932,7 @@ public class Scanner : Object
                     "FlatBed",
                     "Normal",
                     Sane.I18N ("Normal"),
-                    "Document Table" /* Epson scanners, eg. ET-3760 */ 
+                    "Document Table" /* Epson scanners, eg. ET-3760 */
                 };
 
                 string[] adf_sources =
@@ -948,8 +948,7 @@ public class Scanner : Object
                 string[] adf_front_sources =
                 {
                     "ADF Front",
-                    Sane.I18N ("ADF Front"),
-                    "ADF"
+                    Sane.I18N ("ADF Front")
                 };
 
                 string[] adf_back_sources =