CoreCommon: Try several paths in checkedDataRetrieval
CoreTemp: Add alternative path for linux 3.15

Since v3.15-rc1, coretemp temperatures are elsewhere, see
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d72d19c26c417d514787ae85b197af34de286c0a
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bab2243ce1897865e31ea6d59b0478391f51812b
Credits for Tomas
Fix: referencing the correct header in StatFs