Fix for task 1991.

We were using a hard coded path for the failsafe policy, this change
makes sure we honor the compile time path given by the user.
Factor out verify_outputs.h
Factor out processes_select.h
Factor out files_copy.h
Add cf-key into tests' workdir
Remove redundant stub
Remove useless yyerror call in SetAuditVersion
Move proc_keyvalue to libutils
Generic LinkedList implementation.

Data agnostic linked list using reference counting to provide both
implicit sharing and copy on write.