Correct to appropriate error message

[da1suk8]

Error message when ADDRESS_KEY(number-address) is missing is not appropriate.
Please fix it.

cosmwasm/contracts/call-number/src/contract.rs

Lines 55 to 59 in 03abb08

	let address: Addr = from_slice(
	&deps
	.storage
	.get(ADDRESS_KEY)
	.ok_or(ContractError::StorageError)?,

cosmwasm/contracts/call-number/src/error.rs

Lines 10 to 11 in 03abb08

	#[error("Storage does not have the number")]
	StorageError,

[da1suk8]

closed via #321