Fixes/#236 missing osm deu nodes

[IlkaCu]

Fixes #236

[ClaraBuettner]

It solves the problem described in #236 but I run into errors in osmtgmod:

> [2021-04-29 16:23:34,735] {logging_mixin.py:120} WARNING - 04/29/2021 16:23:34 Executing SQL statement 201:
> CREATE TRIGGER problem_log_trigger
> AFTER DELETE ON power_line_sep
> FOR EACH ROW 
> EXECUTE PROCEDURE otg_power_line_as_branch_problem_tg ('dead_end')
> [2021-04-29 16:23:34,748] {__init__.py:526} INFO - Executing SQL statement 202:
> SELECT otg_connect_busses_to_lines_1 ()
> 
> [2021-04-29 16:23:34,748] {logging_mixin.py:120} WARNING - 04/29/2021 16:23:34 Executing SQL statement 202:
> SELECT otg_connect_busses_to_lines_1 ()
> [2021-04-29 16:29:52,437] {__init__.py:533} ERROR - Exception raised with command 202. Check data and code and restart with 'python ego_otg.py egon-data-clara 202'.
> Traceback (most recent call last):
>   File "/home/buettner/egon-data/git/eGon-data/src/egon/data/processing/osmtgmod/__init__.py", line 530, in osmtgmod
>     cur.execute(command)
> psycopg2.errors.InvalidParameterValue: Geometry type (Point) does not match column type (LineString)
> CONTEXT:  PL/pgSQL function otg_connect_busses_to_lines_1() line 81 at assignment
> 
> [2021-04-29 16:29:52,446] {logging_mixin.py:120} WARNING - 04/29/2021 16:29:52 Exception raised with command 202. Check data and code and restart with 'python ego_otg.py egon-data-clara 202'.
> Traceback (most recent call last):
>   File "/home/buettner/egon-data/git/eGon-data/src/egon/data/processing/osmtgmod/__init__.py", line 530, in osmtgmod
>     cur.execute(command)
> psycopg2.errors.InvalidParameterValue: Geometry type (Point) does not match column type (LineString)
> CONTEXT:  PL/pgSQL function otg_connect_busses_to_lines_1() line 81 at assignment
> [2021-04-29 16:29:57,297] {local_task_job.py:102} INFO - Task exited with return code 1

[ClaraBuettner]

The same error in osmtgmod occurs when I delete the 4 substations which have a Point geometry in the Polygon column.