ZOOKEEPER-2993: Removed 'generated' line from .gitignore

Author: asutosh936 <asutosh.pandya@hotmail.com>

Reviewers: Abraham Fine <afine@apache.org>, Andor Molnár <andor@cloudera.com>, Michael Han <hanm@apache.org>

Closes #488 from asutosh936/ZOOKEEPER-2993

(cherry picked from commit 07228badc4691ca96f0d35e5aaa5ebcb2b9891cb)
Signed-off-by: Michael Han <hanm@apache.org>

.gitignore

@@ -52,7 +52,6 @@ tmp/**/*
 .gradle
 *.patch
 *.swp
-generated
 
 # C
 tags