Vim periodically blanks "/" search line while in visual mode

[dbarnett]

What steps will reproduce the problem?

1. Start a8 with session saving enabled
2. Enter visual mode
3. Type "/" and wait a few seconds

Vim blanks out what you were typing.

This is another manifestation of https://code.google.com/p/abominade/issues/detail?id=18.

[dbarnett]

Previous cases of this problem were fixed in df8a2bb758 and 883c1c0bbf. It's just yet another mode we need to detect and block vim from saving session.