CheckSizeArgForCreate checks that size is specified when snapshot or source volume aren't. But when size is 0, CheckSizeArgForCreate action works wrong and generates error: 'Size is a required parameter if snapshot or source volume is not specified', meanwhile user expected to see: 'Volume size '0' must be greater than 0'. Change-Id: I164970a600d6e86bd7076dd485f676a703f5e487 Closes-Bug: #1454276