The change in commit v2.8.12~218^2 (CPackRPM protect '@' character in
filename processed in the spec file, 2013-07-05) was not necessary after
commit v2.8.12~439^2 (Add support for componentized USER spec file,
2013-04-01). The latter replaced ${VAR} references in the spec file
template string with \@VAR\@ references, thus protecting '@' symbols
automatically. This caused CPackRPM to break paths with @ symbols.
Revert the change to fix the behavior, and add a test case.
5857ca5e0d