Teko: Option name inconsistent with Trilinos practice

From lines 13-18 of https://github.com/trilinos/Trilinos/blob/master/packages/teko/CMakeLists.txt

```
TRIBITS_ADD_OPTION_AND_DEFINE(
  Ifpack2_Trilinos
  HAVE_${PACKAGE_NAME}_ENABLE_Ifpack2
  "Enable Ifpack2 preconditioners"
  OFF
  )
```