Fix err_msg not being initialized when check_creates_sql is invoked

Author: talek

plugins/modules/oracle_sqldba

@@ -266,8 +266,9 @@ def run_sql(sql, username, password, pdb):
 
 
 def check_creates_sql(sql, scope):
-    global pdb_list
+    global pdb_list, err_msg
 
+    err_msg = ""
     if not sql.endswith(";"):
         sql += ";"
     if scope == 'cdb':