verify: move manifest verification to its own function This makes verify more modular, making it easier for extensions to extend.

verify: move file cross checking to its own function This is part of making verify more modular so extensions can hook into it.

verify: move filelog verification to its own function This makes verify more modular so extensions can hook in more easily.

verify: move checkentry() to be a class function This is part of making verify more modular so extensions can hook into it.

verify: move checklog() onto class This is part of an effort to make verify more modular so extensions can hook into it.

dockerrpm: fix CentOS 5 RPMs (issue4977) The older rpmbuild in CentOS 5 fails if some of the output directories have not been created yet. This change results in creating those directories.