mksrc.sh: cleanup and fixes

- Added "-i" switch to discard submodules from package
- Fixed patcing of %SHORTVERSION% by removing trailing "."
- Removed hard coded doc path
- Fixed .sha1s file creation

Change-Id: Ieb72c7420875da3d2eec7131af16b2dcd15a146e
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>