avoid Content encoding warning with tests

frameworks/C++/ULib/src/db.usp

@@ -55,7 +55,7 @@ static void usp_end_db()
 #endif
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 pworld_db->id = u_get_num_random(10000);

frameworks/C++/ULib/src/json.usp

@@ -36,7 +36,7 @@ static void usp_end_json()
 #endif
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 #ifndef AS_cpoll_cppsp_DO

frameworks/C++/ULib/src/query.usp

@@ -64,7 +64,7 @@ static void usp_end_query()
 queries;
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 int i = 0, num_queries;

frameworks/C++/ULib/src/rdb.usp

@@ -51,7 +51,7 @@ static void usp_end_rdb()
 #endif
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 UStringRep* rep;

frameworks/C++/ULib/src/rquery.usp

@@ -54,7 +54,7 @@ static void usp_end_rquery()
 queries;
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 World* pworld;

frameworks/C++/ULib/src/rupdate.usp

@@ -54,7 +54,7 @@ static void usp_end_rupdate()
 queries;
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 World* pworld;

frameworks/C++/ULib/src/update.usp

@@ -72,7 +72,7 @@ static void usp_end_update()
 queries;
 -->
 <!--#header
-Content-Type: application/json; charset=UTF-8
+Content-Type: application/json
 -->
 <!--#code
 int i = 0, num_queries;