[master] typo fixed in dhcpv4 option name with code 38, tcp-keepalive-interval

doc/guide/dhcp4-srv.xml

@@ -683,7 +683,7 @@ temporarily override a list of interface names and listen on all interfaces.
 <row><entry>arp-cache-timeout</entry><entry>35</entry><entry>uint32</entry><entry>false</entry></row>
 <row><entry>ieee802-3-encapsulation</entry><entry>36</entry><entry>boolean</entry><entry>false</entry></row>
 <row><entry>default-tcp-ttl</entry><entry>37</entry><entry>uint8</entry><entry>false</entry></row>
-<row><entry>tcp-keepalive-internal</entry><entry>38</entry><entry>uint32</entry><entry>false</entry></row>
+<row><entry>tcp-keepalive-interval</entry><entry>38</entry><entry>uint32</entry><entry>false</entry></row>
 <row><entry>tcp-keepalive-garbage</entry><entry>39</entry><entry>boolean</entry><entry>false</entry></row>
 
           </tbody>

src/lib/dhcp/std_option_defs.h

@@ -130,7 +130,7 @@ const OptionDefParams OPTION_DEF_PARAMS4[] = {
     { "ieee802-3-encapsulation", DHO_IEEE802_3_ENCAPSULATION,
       OPT_BOOLEAN_TYPE, false, NO_RECORD_DEF, "" },
     { "default-tcp-ttl", DHO_DEFAULT_TCP_TTL, OPT_UINT8_TYPE, false, NO_RECORD_DEF, "" },
-    { "tcp-keepalive-internal", DHO_TCP_KEEPALIVE_INTERVAL,
+    { "tcp-keepalive-interval", DHO_TCP_KEEPALIVE_INTERVAL,
       OPT_UINT32_TYPE, false, NO_RECORD_DEF, "" },
     { "tcp-keepalive-garbage", DHO_TCP_KEEPALIVE_GARBAGE,
       OPT_BOOLEAN_TYPE, false, NO_RECORD_DEF, "" },