Make DTObjects thread safe

The static analyzer found that the objects were calling the non-const
version of 'find' for a pointer member variable. By assigning the same
address to a pointer to const we now make sure the const 'find' is called.
Fix of typo in 4 InputTags ...seedeed -> ...seeded.
Merge pull request #6154 from Dr15Jones/threadSafeDTObjects

Make DTObjects thread safe
Merge pull request #6189 from Martin-Grunewald/FixOfInputTags

HLT Fix of typo in 4 InputTags ...seedeed -> ...seeded.
Merge remote branch 'origin/CMSSW_7_3_X' into CMSSW_7_0_X