Fix bug of different-scale option about indentation

[HiromuIshikawa]

This PR purposed to fix bug of --different-scale option caused by wrong indentation.

Used data: data/ex8.dat

# Example Data Set 8 with Categories of different scale
@ People,Income
2007,100,500000
2008,450.23,760000
2009,255,1000000
2010,340,800000
2011,160,600400
2012,200,950000
2014,488,700000

When I plotted 2 categories data (that is above one) having different-scale, the output is as follows:

However, I think the ideal output is to have two normalized plots by category.
So, when I was reading source code of termgraph, I found a wrong indentation in block treating different-scale.

The output after fixing indentation is as follows:

[mkaz]

Nice fix 👍
Thank you for the contribution