Remove dead code: TW_HAS_DUAL_STORAGE

Nothing sets TW_HAS_DUAL_STORAGE. Remove this dead code.

Change-Id: Id5d10c9ee3883dad6beef69e09d16b0f1350c91d
diff --git a/data.cpp b/data.cpp
index 6b0f971..629b4c8 100644
--- a/data.cpp
+++ b/data.cpp
@@ -523,13 +523,7 @@
 	if (varName == "tw_use_external_storage") {
 		string str;
 
-		if (GetIntValue(TW_HAS_DUAL_STORAGE) == 1) {
-			if (value == 0) {
-				str = GetStrValue(TW_INTERNAL_PATH);
-			} else {
-				str = GetStrValue(TW_EXTERNAL_PATH);
-			}
-		} else if (GetIntValue(TW_HAS_INTERNAL) == 1)
+		if (GetIntValue(TW_HAS_INTERNAL) == 1)
 			str = GetStrValue(TW_INTERNAL_PATH);
 		else
 			str = GetStrValue(TW_EXTERNAL_PATH);