Make message string only when necessary

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
Less string concatenation

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
Fix undefined variable

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
Call it 0.6.2

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>