Fix hash check when downloading Clang

[micbou]

I made a mistake in PR #147. The SHA256 option should be set without quotes when downloading Clang. I am not sure why it was working on Travis but it did not work on my linux machine. This is certainly the cmake version.

I also removed some trailing spaces.

Sorry for the trouble.

CLA already signed.

[icholy]

I'm encountering this error as well:

  RAN: '/usr/bin/cmake -G Unix Makefiles -DUSE_CLANG_COMPLETER=ON -DUSE_DEV_FLAGS=ON /home/icholy/Code/src/github.com/icholy/ycmd/cpp'

  STDOUT:


  STDERR:
Your C++ compiler supports C++11, compiling in that mode.
Downloading Clang 3.6
CMake Error at ycm/CMakeLists.txt:87 (file):
  file DOWNLOAD HASH mismatch

    for file: [/home/icholy/Code/src/github.com/icholy/ycmd/cpp/../clang_archives/clang+llvm-3.6.0-x86_64-linux-gnu-ubuntu-14.04.tar.xz]
      expected hash: ["e8396103fbf794e6af671593659458dfe841c32234d3cd4f37be0b48cd6a9f8b"]
        actual hash: [e8396103fbf794e6af671593659458dfe841c32234d3cd4f37be0b48cd6a9f8b]

[micbou]

Yes, the quotes should not be in the expected hash. This PR fixes this.

[Valloric]

Thanks for the PR!