ospfd: compile warning cleanups

A set of patches to clarify some comments as well as cleanup code that was
causing warnings.  After these patches, the code can be compiled with

-Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings
-Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual
-Wextra -Wno-unused-parameter -Wno-missing-field-initializers

(what is current in trunk plus -Wextra -Wno-unused-parameter
-Wno-missing-field-initializers).

Signed-off-by: Scott Feldman <sfeldma@cumulusnetworks.com>
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index a51db24..9a4587d 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -1764,7 +1764,7 @@
   /* Process each LSA received in the one packet.
    *
    * Numbers in parentheses, e.g. (1), (2), etc., and the corresponding
-   * text below are from the stepsin RFC 2328, Section 13.
+   * text below are from the steps in RFC 2328, Section 13.
    */
   for (ALL_LIST_ELEMENTS (lsas, node, nnode, lsa))
     {