starter: Remove starter-specific plugin lists

It hasn't loaded any plugins since d8fdd1018e ("starter: Don't flush
SAs in the kernel"), which was released with 5.3.3.

src/starter/Android.mk

@@ -18,8 +18,7 @@ LOCAL_C_INCLUDES += \
 	$(strongswan_PATH)/src/stroke
 
 LOCAL_CFLAGS := $(strongswan_CFLAGS) \
-	-DIPSEC_SCRIPT='"ipsec"' \
-	-DPLUGINS='"$(strongswan_STARTER_PLUGINS)"'
+	-DIPSEC_SCRIPT='"ipsec"'
 
 LOCAL_MODULE := starter
 

src/starter/Makefile.am

@@ -24,7 +24,6 @@ AM_CPPFLAGS = \
 	-DIPSEC_SCRIPT=\"${ipsec_script}\" \
 	-DDEV_RANDOM=\"${random_device}\" \
 	-DDEV_URANDOM=\"${urandom_device}\" \
-	-DPLUGINS=\""${starter_plugins}\"" \
 	-DDEBUG
 
 AM_CFLAGS = \