Rework askpassd to intelligently handle retries

Now askpassd will exit only when there are no outstanding questions
that we can answer. While this is not the case, askpassd will engage
continued attempts to decrypt the key. The time between attempts is
randomized to prevent a DOS when a datacenter comes back online.

src/plugins/Makefile.am

@@ -29,14 +29,15 @@ decryptd_la_SOURCES = \
 	decryptd/main.c
 
 askpassd_la_SOURCES = \
+	askpassd/question.c \
+	askpassd/question.h \
 	askpassd/askp.c \
 	askpassd/askp.h \
 	askpassd/iface.c \
 	askpassd/iface.h \
 	askpassd/list.c \
 	askpassd/list.h \
-	askpassd/main.c \
-	askpassd/main.h
+	askpassd/main.c
 
 install-data-hook:
 	$(MKDIR_P) $(DESTDIR)/$(DEO_CONF)/decrypt.d