[Version-unspecific] Check whether queryQuoteSwap has returned a quoteErrorResponse

Intended to close #1760
'queryQuoteSaverDeposit uses only queryQuoteSwap's returned err to check queryQuoteSwap success'.

This checks the queryQuoteSwap results in both queryQuoteSaverDeposit and queryQuoteSaverWithdraw;
of the five func query functions in querier_quotes.go,
only queryQuoteSwap is called by other functions in the file,
and it only by queryQuoteSaverDeposit and queryQuoteSaverWithdraw.