Don't assign to a proto_item* if the value won't be used:

Don't assign to a proto_item* if the value won't be used:
 Fixes Coverity 903,935,968,985,997,999,1024,1025,1134;
Remove unneeded #includes;
Do whitespace cleanup.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@37331 f5534014-38df-0310-8fa8-9805f1628bb7