Issue
polyshp2osm.py converter used to write very small lon/lat values in scientific notation. When tiles were created using the osmconvert tool, the tool used to read only the starting digits of the value and never considered the exponenet part, which gave rise to eratic position of nodes and hence eratic boundaries.

Fix
This commit makes the converter write lon/lat values only in decimal notation thus preventing any erratic read/writes.

Reviewers: rahn, nienhueser

Reviewed By: nienhueser

Differential Revision: https://phabricator.kde.org/D2011