fix crash in CtfSpecialSeedGenerator ocurring at run boundaries

move theRegionProducer delete to the destructor
fixes problems online 
discussed in 
https://hypernews.cern.ch/HyperNews/CMS/get/edmFramework/3395/2/1/1/2/1.html

tested in CMSSW_7_2_1_patch1 using the online DQM setup (crash is gone) and then with short matrix to see no differences in output as expected.