digikam: fix bash path

In some places, the path /bin/bash is hardcoded. Since bash is not available at
this location on NixOS, the affected functionality (for example custom scripts
in the batch queue manager) fails. Substitute it by a proper path.

pkgs/by-name/di/digikam/package.nix

@@ -26,6 +26,7 @@
 , x265
 , jasper
 
+, bash
 # For panorama and focus stacking
 , enblend-enfuse
 , hugin
@@ -110,6 +111,13 @@ stdenv.mkDerivation rec {
     cuda_cudart
   ]);
 
+  postPatch = ''
+    substituteInPlace \
+      core/dplugins/bqm/custom/userscript/userscript.cpp \
+      core/utilities/import/backend/cameracontroller.cpp \
+      --replace-fail \"/bin/bash\" \"${lib.getExe bash}\"
+  '';
+
   cmakeFlags = [
     "-DENABLE_MYSQLSUPPORT=1"
     "-DENABLE_INTERNALMYSQL=1"