Fix llvm-3.4.9999 dependencies

`sys-devel/clang-3.4.9999-r100` was dependent on `sys-devel/llvm-3.4.9999`, but `sys-devel/llvm-3.4.9999` was blocking `<=sys-devel/clang-9999-r99`. This fixes that.
```
[ebuild     U *] sys-devel/llvm-3.4.9999:0/3.4.9999::gentoo-opencl [3.3-r2:0/3.3::gentoo] USE="clang libffi multitarget static-analyzer xml -debug -doc -gold -ncurses% -ocaml -python {-test} -udis86" ABI_X86="(64) -32 (-x32)" PYTHON_TARGETS="python2_7 -pypy2_0 -python2_6" VIDEO_CARDS="-radeon" 0 kB
[ebuild  N    *] sys-devel/clang-3.4.9999-r100:0/3.4.9999::gentoo-opencl  USE="multitarget static-analyzer -debug -python" ABI_X86="(64) -32 (-x32)" 0 kB
[blocks B      ] <=sys-devel/clang-9999-r99 ("<=sys-devel/clang-9999-r99" is blocking sys-devel/llvm-3.4.9999)
```