fix typo: sourcemap -> sourceMap

[hn3000]

sourceMap option no longer worked because code expects the M to be upper case, options structure had a lower case m

[hn3000]

Without this fix "jake debug local" fails, because the flag is stored under the wrong name in the options object.

Also: do you need a signed copy of the contribution license agreement for a simple typo? As I understand it, this type of change can't be copyrighted, anyway -- or can it? (I thought I read somewhere that you won't need it, but I can't find where I might have read that.)

[mhegazy]

Thanks for submitting this change, but before we can accept the PR, we will need you to complete and submit the Contributor License Agreement (CLA). Download the agreement (Microsoft Contribution License Agreement.docx), sign, scan, and email it back to cla@microsoft.com.

For more details see https://github.com/Microsoft/TypeScript/blob/master/CONTRIBUTING.md

[hn3000]

I submitted the CLA as requested.

[mhegazy]

thanks!