Fix #11458, pt.3: invoking jam from source dir does not work.

* Adjust build_haiku_repository script to invoke package_repo without
  -C <dir>, as that is not needed and has the unintended side-effect
  of rendering relative package paths non-functional.

build/scripts/build_haiku_repository

@@ -37,8 +37,7 @@ done
 
 # build the repository file
 cp "$repoInfo" "$repositoryDir/repo.info"
-"$packageRepo" create -C "$repositoryDir" "$repositoryDir/repo.info" \
-	"$packageDir"/*.hpkg
+"$packageRepo" create "$repositoryDir/repo.info" "$packageDir"/*.hpkg
 
 # create the checksum file
 $sha256 "$repositoryDir/repo" \