fix(BundleServiceComparator): use ternary operator instead of Integer#compare() that requires API level 19

[DmitriyZaitsev]

Hi! I suggest to replace Integer.compare with ternary operator:

• That method added in API level 19 but Mortar supports much lower API versions;
• Since in this block array lengths are different, so result can be only 1 or -1 and now it's more obvious for reading.

[rjrjr]

Wow, that's nuts. Thanks for the fix, but please sign our CLA so that I can merge it. https://github.com/square/mortar/blob/master/CONTRIBUTING.md

[DmitriyZaitsev]

I've signed it. Thanks.