sql: Remove unused cred.sql snippet

src/libcharon/plugins/sql/cred.sql

@@ -1,24 +0,0 @@
-
-DROP TABLE IF EXISTS shared_secrets;
-CREATE TABLE shared_secrets (
-	id INTEGER PRIMARY KEY AUTOINCREMENT,
-	type INTEGER,
-	local TEXT, 
-	remote TEXT
-);
-
-DROP TABLE IF EXISTS certificates;
-CREATE TABLE certificates (
-	id INTEGER PRIMARY KEY AUTOINCREMENT,
-	type INTEGER,
-	subject TEXT,
-	data BLOB,
-);
-
-DROP TABLE IF EXISTS private_keys;
-CREATE TABLE private_keys (
-	id INTEGER PRIMARY KEY AUTOINCREMENT,
-	type INTEGER,
-	keyid BLOB,
-	data BLOB,
-);