Fixed error messages from DROP VIEW to align with DROP TABLE

- Produce a "Note" for all wrongly dropped objects
  (Like doing DROP VIEW on a table).
- IF EXISTS ends with a list of all not existing objects, instead of a
  separate note for every not existing object.

Other things:
 - Fixed bug where one could do CREATE TEMPORARY SEQUENCE multiple times
   and create multiple temporary sequences with the same name.

mysql-test/main/create_drop_view.result

@@ -61,5 +61,6 @@ Warnings:
 Note	4092	Unknown VIEW: 'test.v1'
 DROP VIEW IF EXISTS t1;
 Warnings:
+Warning	1347	'test.t1' is not of type 'VIEW'
 Note	4092	Unknown VIEW: 'test.t1'
 DROP TABLE t1;

mysql-test/main/drop.result

@@ -209,10 +209,7 @@ Note	1051	Unknown table 'test.table1'
 Note	1051	Unknown table 'test.table2'
 DROP VIEW IF EXISTS view1,view2,view3,view4;
 Warnings:
-Note	4092	Unknown VIEW: 'test.view1'
-Note	4092	Unknown VIEW: 'test.view2'
-Note	4092	Unknown VIEW: 'test.view3'
-Note	4092	Unknown VIEW: 'test.view4'
+Note	4092	Unknown VIEW: 'test.view1,test.view2,test.view3,test.view4'
 
 # Test error message when trigger does not find table
 CREATE TABLE table1(a int);

mysql-test/main/drop_combinations.inc

@@ -0,0 +1,24 @@
+#
+# Create all tables, sequences and views needed for drop combinations;
+#
+
+if ($create_option != 'temporary')
+{
+  show tables;
+}
+
+--echo # Generating test tables
+--disable_query_log
+--disable_warnings
+eval create $create_option table if not exists t1 (a int);
+eval create $create_option table if not exists t2 (a int);
+eval create $create_option sequence if not exists s1;
+eval create $create_option sequence if not exists s2;
+if ($create_option != 'temporary')
+{
+  eval create view if not exists v1 as SELECT * from t1;
+  eval create view if not exists v2 as SELECT * from t2;
+}
+
+--enable_warnings
+--enable_query_log