add genconfig line

* without `genconfig`, warewulfd doesn not read `/etc/warewulf/warewuld.conf`, and read `/usr/local/etc/warewulf/warewulf.conf` instead.
* added `genconfig` line to make our build configuration identical to rpm package one 

This fix #847

userdocs/quickstart/el8.rst

@@ -13,6 +13,22 @@ Install Warewulf and dependencies
 
    git clone https://github.com/hpcng/warewulf.git
    cd warewulf
+   make genconfig \
+    PREFIX=/usr \
+    BINDIR=/usr/bin \
+    SYSCONFDIR=/etc \
+    DATADIR=/usr/share \
+    LOCALSTATEDIR=/var/lib \
+    SHAREDSTATEDIR=/var/lib \
+    MANDIR=/usr/share/man \
+    INFODIR=/usr/share/info \
+    DOCDIR=/usr/share/doc \
+    SRVDIR=/var/lib \
+    TFTPDIR=/var/lib/tftpboot \
+    SYSTEMDDIR=/usr/lib/systemd/system \
+    BASHCOMPDIR=/etc/bash_completion.d/ \
+    FIREWALLDDIR=/usr/lib/firewalld/services \
+    WWCLIENTDIR=/warewulf
    make all
    sudo make install