testsuite: add test not-reportable

Testing make_description to print not-reportable.
lib: make_description show not-reportable

When the flag from desc_flags is set to MAKEDESC_SHOW_URLS and problem is
not-reportable. The abrt-cli shows not-reportable in listing.

Related: rhbz#1066520
Merge pull request #275 from abrt/rhbz1066520_description_not_reportable

Add not-reportable to make_description