Use autoconf to replace @VERSION@ in manpages

configure.ac

@@ -310,5 +310,11 @@ AC_CONFIG_FILES([Makefile
 		 src/zscanner/test/cases/06-3_INCLUDE.in:src/zscanner/test/cases/06-3_INCLUDE.inin
 		 src/zscanner/test/cases/06-4_INCLUDE.in:src/zscanner/test/cases/06-4_INCLUDE.inin
 		 src/zscanner/test/cases/06-0_INCLUDE.in:src/zscanner/test/cases/06-0_INCLUDE.inin
+		 man/khost.1
+		 man/knotc.8
+		 man/knotd.8
+		 man/kdig.1
+		 man/knsupdate.1
+		 man/knot.conf.5
 		 ])
 AC_OUTPUT

man/Makefile.am

 MANPAGES = knot.conf.5 knotc.8 knotd.8 kdig.1 khost.1 knsupdate.1
-
-.5in.5:
-	$(SED) 's;\@VERSION\@;@VERSION@;g' $< > $@
-.8in.8:
-	$(SED) 's;\@VERSION\@;@VERSION@;g' $< > $@
-
 dist_man_MANS = $(MANPAGES)
-CLEANFILES = $(MANPAGES)