FBDECT: Temperature fix, as sent by AVM


git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6268 2b470e98-0d58-463d-a4d8-8e2adae1ed80
OWTHERM_GetValues: fix returnvalue

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6269 2b470e98-0d58-463d-a4d8-8e2adae1ed80
OWTHERM: increase version to 5.23

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6270 2b470e98-0d58-463d-a4d8-8e2adae1ed80