Name union to prevent compiler warning #7146

After merging #6914, a lot of compiler warnings are emitted by clang:

  CXX      test/test_test_bitcoin-main_tests.o
In file included from test/main_tests.cpp:5:
In file included from ./chainparams.h:11:
In file included from ./primitives/block.h:9:
In file included from ./primitives/transaction.h:9:
In file included from ./amount.h:9:
In file included from ./serialize.h:23:
./prevector.h:419:13: warning: template argument uses unnamed type [-Wunnamed-type-template-args]
            std::swap(_union, other._union);
            ^~~
./script/script.h:618:23: note: in instantiation of member function 'prevector<28, unsigned char, unsigned int, int>::swap' requested here
        CScriptBase().swap(*this);
                      ^
./prevector.h:143:5: note: unnamed type used in template argument was declared here
    union {
    ^
1 warning generated.

ACK

But if you're going to give it a name anyway, better make it a descriptive one, like "direct_or_indirect"?

I was about to use foo 8) I'll wait for other ideas (but your name is OK for me).

ACK once it uses a proper name.

@jonasschnelli And do you have an opinion the correct name? Do you agree with direct_or_indirect as @sipa offered?

direct_or_indirect

Better than _somename

direct_or_indirect sounds after the purpose of the union, so yes, would be better then _somename.

ACK 1812de90915d002206148e7beae67d79d7a90e54

OK, thanks for your opinions. Name update.

utACK 1812de9 mod travis

utACK Tested ACK