Make gbuild-to-ide bail out before parsing if ide type is invalid

Also fix the vim modeline to maintain consistant formatting

Change-Id: Ia42ec2a69f9c3037a6390ca4f5c4198031b7aa64
Reviewed-on: https://gerrit.libreoffice.org/11632
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>