No needless dropping of 'estimated_town_class'

To enable the crossing of a city along rivers, only one line of code in the profile text needs to be adjusted:
```
assign townpenalty
    switch  estimated_town_class= 1.0
...
```
->
```
assign townpenalty
    switch or estimated_town_class= ( not estimated_river_class= ) 1.0
...
```

Author: quaelnix

misc/scripts/mapcreation/brouter.sql

@@ -675,15 +675,6 @@ WHERE losmid IN (
         WHERE
             forest_class NOT IN ('1'));
 
-DELETE FROM town_tags
-WHERE losmid IN (
-        SELECT
-            losmid
-        FROM
-            river_tags
-        WHERE
-            river_class NOT IN ('1'));
-
 SELECT
     count(*)
 FROM