Merge branch 'clang_fixes' into maint-0.2.2

changes/dirvote_null_deref

changes/mdesc_null_deref

src/or/circuitbuild.c

src/or/connection.c

src/or/connection_or.c

src/or/control.c

src/or/dirvote.c

src/or/microdesc.c

src/or/or.h