Revert a fix for #101 to fix broken tests relating to `PYENV_NATIVE_EXT`

libexec/pyenv

@@ -28,8 +28,6 @@ if [ -z "$READLINK" ]; then
   exit 1
 fi
 
-unset GREP_OPTIONS
-
 resolve_link() {
   $READLINK "$1"
 }

test/libexec/pyenv-grep

@@ -1,2 +0,0 @@
-#!/usr/bin/env bash
-grep -E "$@"

test/pyenv_ext.bats

@@ -1,11 +1,3 @@
 #!/usr/bin/env bats
 
 load test_helper
-
-@test "conflicting GREP_OPTIONS" {
-  file="${BATS_TMPDIR}/hello"
-  echo "hello" > "$file"
-  GREP_OPTIONS="-F" run pyenv grep "hell." "$file"
-  assert_success
-  assert_output "hello"
-}