[3418] Changes after review

 - example config files are now installed
 - example in section 5.2 configures persistent database

doc/Makefile.am

@@ -2,6 +2,10 @@ SUBDIRS = guide design
 
 EXTRA_DIST = version.ent.in differences.txt Doxyfile Doxyfile-xml
 
+nobase_dist_doc_DATA  = examples/kea4/single-subnet.json
+nobase_dist_doc_DATA += examples/kea4/several-subnets.json
+nobase_dist_doc_DATA += examples/kea6/several-subnets.json
+
 devel:
 	mkdir -p html
 	(cat Doxyfile; echo PROJECT_NUMBER=$(PACKAGE_VERSION)) | doxygen - > html/doxygen.log 2> html/doxygen-error.log

doc/guide/dhcp4-srv.xml

@@ -81,7 +81,9 @@
 
 # Next we specify the type of lease database
     "lease-database": {
-        "type": "memfile"
+        "type": "memfile",
+        "persist": true,
+        "name": "/var/kea/dhcp4.leases"
     },
 
 # Finally, we list the subnets from which we will be leasing addresses.