Python compat - no explicit reference to Python version

Update documentation and shebang.

Differential Revision: https://reviews.llvm.org/D56252

llvm-svn: 350327
diff --git a/llvm/docs/TestSuiteGuide.md b/llvm/docs/TestSuiteGuide.md
index fe7a278..0d9bbac 100644
--- a/llvm/docs/TestSuiteGuide.md
+++ b/llvm/docs/TestSuiteGuide.md
@@ -17,7 +17,7 @@
 
    ```bash
    % mkdir venv
-   % virtualenv -p python2.7 venv
+   % virtualenv venv
    % . venv/bin/activate
    % pip install svn+http://llvm.org/svn/llvm-project/llvm/trunk/utils/lit
    % lit --version