[ready-for-core-team-review]CRM-19585, fixed tax issues

[pradpnayak]

• CRM-19585: Sales tax issue

[pradpnayak]

To replicate
Add Sales tax Relationship For Donation Financial type with 10% tax

1. Create contribution from New contribution form for FT = Donation and Amount = 100
   expected result:
   total amount = 110
   contrbution.tax_amount = 10

actual result:
total amount = 110
contrbution.tax_amount = 10.10

And

2. Create Contribution from New contribution form for FT = Campaign Contribution and Amount = 100
   expected result:
   total amount = 100

actual result:
total amount = 100.10

[jitendrapurohit]

Both above mentioned issues are fixed.