Better fix instead of r34099

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34102 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Using kernel precision when computing LocusEquation (can be backported to 4.4)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34103 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e