Improve tripwire install so there is no prompt to overwrite

src/freedombone-base-tripwire

@@ -80,10 +80,17 @@ function install_tripwire {
       echo 'TEMPDIRECTORY =/tmp';
       echo "MAILFROMADDRESS =tripwire@\$(HOSTNAME)"; } > /etc/tripwire/twcfg.txt
 
+    if [ -f "/etc/tripwire/${HOSTNAME}-local.key" ]; then
+        rm "/etc/tripwire/${HOSTNAME}-local.key"
+    fi
     echo '
 
        ' | twadmin --generate-keys -L "/etc/tripwire/${HOSTNAME}-local.key" -S "/etc/tripwire/${HOSTNAME}-site.key"
 
+    if [ -f "/etc/tripwire/${HOSTNAME}-site.key" ]; then
+        rm "/etc/tripwire/${HOSTNAME}-site.key"
+    fi
+
     echo '
 
        ' | twadmin --create-cfgfile -S "/etc/tripwire/${HOSTNAME}-site.key" /etc/tripwire/twcfg.txt
@@ -142,6 +149,10 @@ function install_tripwire {
     # site key name
     sed -i "s|\$(TWETC)/site.key|\$(TWETC)/\$(HOSTNAME)-site.key|g" /etc/tripwire/twpol.txt
 
+    if [ -f "/etc/tripwire/${HOSTNAME}-site.key" ]; then
+        rm "/etc/tripwire/${HOSTNAME}-site.key"
+    fi
+
     # create the policy
     echo '