Remove mentioning of build directory in README.md

Fix apple#3098

README.md

@@ -46,7 +46,7 @@ Once you have your dependencies, you can run cmake and then build:
 
 1. Check out this repository.
 1. Create a build directory (you can have the build directory anywhere you
-   like). There is currently a directory in the source tree called build, but you should not use it. See [#3098](https://github.com/apple/foundationdb/issues/3098)
+   like).
 1. `cd <PATH_TO_BUILD_DIRECTORY>`
 1. `cmake -G Ninja <PATH_TO_FOUNDATIONDB_DIRECTORY>`
 1. `ninja # If this crashes it probably ran out of memory. Try ninja -j1`