Fix some bugaboos with comparing_decimals_2

Test Plan:
Load http://exercises.ka.local/exercises/comparing_decimals_2.html?debug&problem=rearranging
Don't see console errors about TRAILING1 being undefined
Verify hints work
Refresh http://exercises.ka.local/exercises/comparing_decimals_2.html?debug&problem=rearranging until the answer is "="
Don't see console errors about i being undefined; Verify hints work
Load http://exercises.ka.local/exercises/comparing_decimals_2.html?debug&problem=adding-zeros a few times to verify it still works too

Auditors: peter