TStationHitManager.h - Reorder includes to avoid tripping over a GCC ICE

Hope should fix build errors such as with the +avx2+fma builds at

https://lhcb-nightlies.cern.ch/nightly/lhcb-gaudi-head/build/2322/

@cattanem Hope its OK, but I have added the label to build this in lhcb-gaudi-head