use default shell (mksh) in emulator

remove the override to use ash as shell so that mksh is the
default in 'generic' product type

Change-Id: I91d76d0fc522baf5d47096ab19ea264c9b1268e6
diff --git a/target/board/generic/BoardConfig.mk b/target/board/generic/BoardConfig.mk
index bc999fa..807125a 100644
--- a/target/board/generic/BoardConfig.mk
+++ b/target/board/generic/BoardConfig.mk
@@ -29,9 +29,6 @@
 # no hardware camera
 USE_CAMERA_STUB := true
 
-# Set /system/bin/sh to ash, not mksh, to make sure we can switch back.
-TARGET_SHELL := ash
-
 # Enable dex-preoptimization to speed up the first boot sequence
 # of an SDK AVD. Note that this operation only works on Linux for now
 ifeq ($(HOST_OS),linux)
diff --git a/target/board/generic_x86/BoardConfig.mk b/target/board/generic_x86/BoardConfig.mk
index c62b0a4..da597e8 100644
--- a/target/board/generic_x86/BoardConfig.mk
+++ b/target/board/generic_x86/BoardConfig.mk
@@ -18,9 +18,6 @@
 # no hardware camera
 USE_CAMERA_STUB := true
 
-# Set /system/bin/sh to ash, not mksh, to make sure we can switch back.
-TARGET_SHELL := ash
-
 # Enable dex-preoptimization to speed up the first boot sequence
 # of an SDK AVD. Note that this operation only works on Linux for now
 ifeq ($(HOST_OS),linux)