Avoid clang error in rootcling

[wmtan]

A recent carry forward from the 7_2_X branch introduced a header for dictionary processing that clang cannot parse. This pull request hides the offending line of code from rootcling (genreflex),, thereby fixing the fatal build error in the ROOT6 IB.
Note: the same header fails to compile in the CLANG IB.
Please merge this trivial request as soon as convenient.

[cmsbuild]

A new Pull Request was created by @wmtan for CMSSW_7_2_ROOT6_X.

Avoid clang error in rootcling

It involves the following packages:

PhysicsTools/SelectorUtils

@cmsbuild, @vadler, @nclopezo, @monttj can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.

[vadler]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_2_ROOT6_X IBs unless changes or unless it breaks tests.

[lgray]

@wmtan what does clang want instead (so that I can fix this when we switch or add a #elif)?

[Dr15Jones]

I think typename should be removed.

[lgray]

Ok, gcc wanted the typename there iirc. Then again gcc doesn't seem to care so much about the correct use of that keyword. I'll fix this in another PR.

[wmtan]

FWIW, the other C++ guru I consulted (Marc Paterno) also indicated that typename is wrong and should be removed. He was surprised that gcc accepted it.

[lgray]

As far as I can tell gcc seems to not care as long as you have enough 'typename's to satisfy a given situation... beyond that seems to treat it as no-op.

[wmtan]

Can this be merged? It is somewhat urgent as it fixes a compilation error, and several knock-on link errors, in the IB.