Fix4390 stable5

fixes #4390 for stable5, needs forward port

fixes dnd into folders ending in whitespace on oracle
unnecessary portability option because only affects fixed length character columns. luckily we dont have that kind of columns: the text datatype is transformed into varchar by MDB2

@karlitschek @DeepDiver1975 please review

@bartv2 I don't know if doctrine also rtrims all data? could you check to make sure we don't have a problem in OC6? Maybe forward port the unit test? I'm busy with OC4.5 -> OC5 migration on oracle.