Maybe standardize SKIP_* in generate-git-snapshot

[CyrilBrulebois]

There are several ways to use SKIP_* variables:

if [ "${SKIP_DCH:-}" = "true" ]
if [ "${SKIP_BRANCH_AND_TAG_HANDLING:-}" = "true" ] ;

if [ -n "${SKIP_GIT_CLEANUP:-}" ] ;
if [ -n "${SKIP_QUILT_CLEANUP:-}" ] ;

It might be nice to standardize on checking whether each variable is set to true? The downside is that people setting the GIT or QUILT one manually might get a different behaviour all of a sudden… On the plus side, one of them is set automatically from another part of the script, and the info message mentions explicitly setting them to true anyway.

No practical issue except for consistency and ease of documentation (another bug report coming up).

[CyrilBrulebois]

Bug report filed against the website → mika/jenkins-debian-glue.org#14