zebra: Some code cleanup based upon Review.

zebra: Some code cleanup based upon Review.

Cleanup 2 spots in the code:
1) In if_netlink.c -> combine multi-line if statement into 1 line
2) In zebra_ptm.c -> only handle code that needs to be inside the if statement
in the if statement.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>