fix ansible-lint warnings

[lhoss]

During my work of integrating molecule testing (see #60), I got following 'ansible-lint' warnings (that need to be fixed, before molecule runs the actual tests):

➜  ansible-zookeeper git:(master) ✗ molecule verify
--> Executing ansible-lint...
[ANSIBLE0002] Trailing whitespace
/Users/lhoss/IdeaProjects/ansible-zookeeper/meta/main.yml:10
  # the ones that apply to your role. If you don't see your

[ANSIBLE0002] Trailing whitespace
/Users/lhoss/IdeaProjects/ansible-zookeeper/meta/main.yml:116


[ANSIBLE0006] tar used in place of unarchive module
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:12
Task/Handler: Unpack tarball.

[ANSIBLE0006] tar used in place of unarchive module
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:12
Task/Handler: Unpack tarball.

[ANSIBLE0011] All tasks should be named
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:16
Task/Handler: group name=zookeeper system=yes

[ANSIBLE0011] All tasks should be named
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:16
Task/Handler: group name=zookeeper system=yes

[ANSIBLE0011] All tasks should be named
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:17
Task/Handler: user system=yes name=zookeeper group=zookeeper

[ANSIBLE0011] All tasks should be named
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:17
Task/Handler: user system=yes name=zookeeper group=zookeeper

[ANSIBLE0009] Octal file permissions must contain leading zero
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:42
Task/Handler: Add zookeeper's bin dir to the PATH

[ANSIBLE0009] Octal file permissions must contain leading zero
/Users/lhoss/IdeaProjects/ansible-zookeeper/tasks/tarball.yml:42
Task/Handler: Add zookeeper's bin dir to the PATH

Note: Even though these warnings might be sometimes of 'subjective' nature, I aim to follow them (on the roles I will gradually move to molecule).
I'ld work on fixing myself (but only later this week), unless somebody is faster :)

[lhoss]

Updated: Here's my initial work, see: #60