fix raise syntax
fix raise syntax

This takes a single argument (the error message), not multiple
arguments that get formatted implicitly.

Change-Id: Idfbc913ea9f93820edb7e955e9e4f57618c8cd1b

gabbayo/git-repo,GerritCodeReview/git-repo,couchbasedeps/git-repo,lipro-yocto/git-repo,mer-tools/git-repo,couchbasedeps/git-repo,codetutil/git-repo,codetutil/git-repo,lipro-yocto/git-repo,lewixliu/git-repo,TheQtCompany/git-repo,gabbayo/git-repo,aosp-mirror/tools_repo,mer-tools/git-repo,GerritCodeReview/git-repo,TheQtCompany/git-repo,aosp-mirror/tools_repo,lewixliu/git-repo