packaging: spec: cleanup

No functionality change!

1. fix alignments.

2. fix shell styles.

3. quote everything.

4. remove useless obvious comments.

5. reorder sections.

6. reorder %files to plain sort

7. reorder dependencies to plain sort

8. prefix internal variables to avoid conflict and confusion.

9. add / suffix for directories at %files.

Change-Id: I284a640121874544e0c3e57f52bc1722e50af871
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>