Remove unused pubsub module.

src/common/include.am

@@ -68,7 +68,6 @@ LIBOR_A_SRC = \
   src/common/container.c				\
   src/common/log.c					\
   src/common/memarea.c					\
-  src/common/pubsub.c					\
   src/common/util.c					\
   src/common/util_bug.c					\
   src/common/util_format.c				\
@@ -161,7 +160,6 @@ COMMONHEADERS = \
   src/common/memarea.h				\
   src/common/linux_syscalls.inc			\
   src/common/procmon.h				\
-  src/common/pubsub.h				\
   src/common/sandbox.h				\
   src/common/storagedir.h			\
   src/common/testsupport.h			\