After-merge cleanup: adjust the test to work in 10.0

For the original test in 10.0 it was not really important if
find_user_wild() or find_user_exact() is used in sp_grant_privileges().
sp-security.test passed with either of them.

Fixing the test so it reliably fails with find_user_wild()
and pass with find_user_exact().

mysql-test/r/sp-security.result

@@ -618,7 +618,9 @@ SELECT 1	latin1	latin1_swedish_ci	latin1_swedish_ci
 DROP USER user2@localhost;
 DROP DATABASE db1;
 create user foo@local_ost;
-create user foo@`local\_ost` identified by 'nevermore';
+create user foo@`local\_ost`;
+update mysql.user set plugin='foobar' where host='local\\_ost';
+flush privileges;
 create database foodb;
 grant create routine on foodb.* to foo@local_ost;
 select user(), current_user();

mysql-test/t/sp-security.test

@@ -999,7 +999,16 @@ DROP DATABASE db1;
 # Bug#27407480: AUTOMATIC_SP_PRIVILEGES REQUIRES NEED THE INSERT PRIVILEGES FOR MYSQL.USER TABLE
 #
 create user foo@local_ost;
-create user foo@`local\_ost` identified by 'nevermore';
+#
+# Create a user with an authentification plugin 'foobar'.
+# Instead of using a normal "CREATE USER <user> IDENTIFIED VIA <plugin>"
+# we do CREATE (without VIA) followed by UPDATE and FLUSH.
+# This is to avoid installing a real plugin and thus avoid the test dependency.
+# We won't login under this user in the below test, so this is fine.
+#
+create user foo@`local\_ost`;
+update mysql.user set plugin='foobar' where host='local\\_ost';
+flush privileges;
 create database foodb;
 grant create routine on foodb.* to foo@local_ost;
 connect con1,localhost,foo;