modules.apache: 2-space indents => 4-space indents

Fixes part of Travis.
```
************* Module salt.modules.apache
W0311:260,0: Bad indentation. Found 6 spaces, expected 8
W0311:262,0: Bad indentation. Found 6 spaces, expected 8
W0311:264,0: Bad indentation. Found 6 spaces, expected 8
W0311:273,0: Bad indentation. Found 6 spaces, expected 8
W0311:275,0: Bad indentation. Found 6 spaces, expected 8
W0311:281,0: Bad indentation. Found 6 spaces, expected 8
W0311:283,0: Bad indentation. Found 6 spaces, expected 8
W0311:285,0: Bad indentation. Found 6 spaces, expected 8
W0311:296,0: Bad indentation. Found 6 spaces, expected 8
W0311:298,0: Bad indentation. Found 6 spaces, expected 8
W0311:304,0: Bad indentation. Found 6 spaces, expected 8
W0311:306,0: Bad indentation. Found 6 spaces, expected 8
W0311:308,0: Bad indentation. Found 6 spaces, expected 8
```