Hide API keys in error messages

[joshuaulrich]

Error messages contain API keys in plain text. This is a problem for tests that are run on TravisCI, or any other CI platform where the logs are public.

Here are a couple examples:

quantmod::getQuote(c("FOO", "WYSIWYG"), src = "av", api.key = v)
Error in getQuote.av(Symbols = c("FOO", "WYSIWYG"), api.key = "[redacted]") : 
  No data for symbols: FOO, WYSIWYG

quantmod::getQuote(c("FOO", "WYSIWYG"), src = "tiingo", api.key = k)
Error in getQuote.tiingo(Symbols = c("FOO", "WYSIWYG"), api.key = "[redacted]") : 
  No data for symbols: FOO, WYSIWYG

The fix may be as easy as setting call. = FALSE in the call to stop().