Allow enviroment variables in dhcp-script to contain '='

An ancient miss-reading of "man setenv" lead to code which strips
'=' characters from the contents of enviroment variables set
in the dhcp-script. Equals characters are, of course banned in the
_name_ of environment variables, not the _value_.

src/helper.c

@@ -712,13 +712,7 @@ static unsigned char *grab_extradata(unsigned char *buf, unsigned char *end,  ch
 	  break;
 
       if (next && (next != buf))
-	{
-	  char *p;
-	  /* No "=" in value */
-	  if ((p = strchr((char *)buf, '=')))
-	    *p = 0;
-	  val = (char *)buf;
-	}
+	val = (char *)buf;
     }
   
   my_setenv(env, val, err);