For the generic board, set /system/bin/sh to mksh to test the transition

Change-Id: I778bae4060dd404e82fbf9dd5b8a2024c8268402
diff --git a/target/board/generic/BoardConfig.mk b/target/board/generic/BoardConfig.mk
index 2b72d01..f630dac 100644
--- a/target/board/generic/BoardConfig.mk
+++ b/target/board/generic/BoardConfig.mk
@@ -9,3 +9,6 @@
 TARGET_CPU_ABI := armeabi
 HAVE_HTC_AUDIO_DRIVER := true
 BOARD_USES_GENERIC_AUDIO := true
+
+# Set /system/bin/sh to mksh, not ash, to test the transition.
+TARGET_SHELL := mksh