wrong order in series

[pernici]

The series method with precision `prec` sometimes in presence of 
`log(x)` terms converts the order to `O(x**prec * log(x)**k`)
as in this example

```
>>> from sympy import *
>>> x = Symbol('x')
>>> (sin(x)*log(x)).series(x,0,4)
x*log(x) - x**3*log(x)/6 + O(x**4*log(x))
```

some other times it gives the requested order
```
>>> (x**2*(x**3 + x**2 + 1)*log(x)).series(x, 0, 4)
x**2*log(x) + x**4*log(x) + O(x**4)
```

which is the correct behavior

Original issue for #6179: http://code.google.com/p/sympy/issues/detail?id=3080
Original author: https://code.google.com/u/107755593449647463741/

[asmeurer]

**Labels:** Series  

Original comment: http://code.google.com/p/sympy/issues/detail?id=3080#c1
Original author: https://code.google.com/u/asmeurer@gmail.com/

[asmeurer]

**Status:** Valid  

Original comment: http://code.google.com/p/sympy/issues/detail?id=3080#c2
Original author: https://code.google.com/u/asmeurer@gmail.com/

[skirpichev]

https://github.com/sympy/sympy/pull/2411

**Labels:** NeedsReview  

Original comment: http://code.google.com/p/sympy/issues/detail?id=3080#c3
Original author: https://code.google.com/u/113518207426301808764/

[anutosh491]

This issue still persists on master.