Fix an Isearch var to be a string (Bug#23038)

* isearch.el (isearch--describe-regexp-mode): The `description' var
  needs to always be a string.  Add the missing default case for the
  cond form that ensures that.

Before this bug fix, for the events when `regexp-function' and
`search-default-mode' both were nil, `description' also stayed nil.  So
when `space-before' was non-nil, the "non-string" `description'
(with a value of nil) got passed as an argument to
`replace-regexp-in-string' (where a string was expected).  That caused
the error described in Bug#23038.

0 files changed, 0 insertions, 0 deletions