Stupid error message for 'insert "aaa"' into decimal column fixed

mysql-test/r/row.result:
  test result fixed
sql/item.cc:
  error message for the case of bad decimal value added
  duplicated code removed

mysql-test/r/row.result

@@ -15,7 +15,7 @@ select row('a',1.5,3) IN (row(1,2,3), row('a',1.5,3), row('a','a','a'));
 row('a',1.5,3) IN (row(1,2,3), row('a',1.5,3), row('a','a','a'))
 1
 Warnings:
-Error	1366	Incorrect decimal value: '' for column '' at row -1
+Warning	1292	Truncated incorrect DECIMAL value: 'a'
 select row('a',0,3) IN (row(3,2,3), row('a','0','3'), row(1,3,3));
 row('a',0,3) IN (row(3,2,3), row('a','0','3'), row(1,3,3))
 1

sql/item.cc

@@ -260,8 +260,15 @@ my_decimal *Item::val_decimal_from_string(my_decimal *decimal_value)
     return 0;                                   // NULL or EOM
 
   end_ptr= (char*) res->ptr()+ res->length();
-  str2my_decimal(E_DEC_FATAL_ERROR, res->ptr(), res->length(), res->charset(),
-                 decimal_value);
+  if (str2my_decimal(E_DEC_FATAL_ERROR & ~E_DEC_BAD_NUM,
+                     res->ptr(), res->length(), res->charset(),
+                     decimal_value) & E_DEC_BAD_NUM)
+  {
+    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                        ER_TRUNCATED_WRONG_VALUE,
+                        ER(ER_TRUNCATED_WRONG_VALUE), "DECIMAL",
+                        str_value.c_ptr());
+  }
   return decimal_value;
 }
 
@@ -1457,10 +1464,7 @@ void Item_string::print(String *str)
 
 my_decimal *Item_string::val_decimal(my_decimal *decimal_value)
 {
-  /* following assert is redundant, because fixed=1 assigned in constructor */
-  DBUG_ASSERT(fixed == 1);
-  string2my_decimal(E_DEC_FATAL_ERROR, &str_value, decimal_value);
-  return (decimal_value);
+  return val_decimal_from_string(decimal_value);
 }