Improve error handling on SqlPackage.
Improve error handling on SqlPackage.

* If custom path to SQL Package is used, show that one if it is invalid.
* If error occurs during SQL Package deployment, do not output error to stderr.

beeker/FAKE,MiloszKrajewski/FAKE,beeker/FAKE,MiloszKrajewski/FAKE,beeker/FAKE,MiloszKrajewski/FAKE,MiloszKrajewski/FAKE,beeker/FAKE