scan-build: check all results, fix or suppress

Submitted by Patrick Ohly `@pohly`

Assigned to SyncEvolution Community

Nightly testing now includes a compile run with clang's scan-build. The result is available under clang-amd64/scan-build.

Some of the reports have been analyzed, but not all. Still need to do that.

If new reports show up, the "compile" step for clang-amd64 will fail, so at least we will catch new problems.

Version: 1.4