Revert "Avoid choosing virtualenv when building PyPy from source"

This reverts commit 63c00d99899971c3ed9a3ee01c69b8b3a194e171.

plugins/python-build/bin/pyenv-install

@@ -207,13 +207,9 @@ if [ -z "${PYENV_BOOTSTRAP_VERSION}" ]; then
     else
       for version in $(pyenv-versions --bare | sort -r); do
         if [[ "${version}" == "2.7"* ]]; then
-          if [ -f "$(pyenv-prefix "${version}")/bin/activate" ]; then
-            : # avoid choosing virtualenv since it may not have some necessary modules (e.g. cffi, pycparser)
-          else
           PYENV_BOOTSTRAP_VERSION="$version"
           break
         fi
-        fi
       done
     fi
     if [ -n "$PYENV_BOOTSTRAP_VERSION" ]; then