Zookeeper: Yosemite fixes

Closes #32900.
Maybe personal preference but I find:
```ruby
if MacOS.version == :yosemite
  patch :p0 do
    url "https://issues.apache.org/jira/secure/attachment/12672517/ZOOKEEPER-2049.noprefix.branch-3.4.patch"
    sha1 "001424dacb82209c12653b3fbcdc0847a41f4294"
  end
end
```
more readable