bug#54775: debbugs uses functions not available in Emacs 25.1

[Jonas Bernoulli]

Debbugs claims to support Emacs 25.1 but uses functions/arguments that
are not available in that release:

In debbugs-gnu-package-tabulated-list-print:
lib/debbugs/debbugs-gnu.el:735:36:Warning: alist-get called with 5 arguments,
    but accepts only 2-4

In debbugs-gnu-show-all-blocking-reports:
lib/debbugs/debbugs-gnu.el:1404:14:Warning: alist-get called with 5 arguments,
    but accepts only 2-4

In debbugs-gnu-emacs-release-blocking-reports:
lib/debbugs/debbugs-gnu.el:1429:7:Warning: ‘(id (alist-get release
    debbugs-gnu-emacs-blocking-reports nil nil (function equal)))’ is a
    malformed function
lib/debbugs/debbugs-gnu.el:1433:70:Warning: reference to free variable ‘id’
lib/debbugs/debbugs-gnu.el:1434:33:Warning: reference to free variable
    ‘blockers’

In debbugs-gnu-jump-to-bug:
lib/debbugs/debbugs-gnu.el:2105:24:Warning: attempt to let-bind nonvariable
    ‘(memql bugid (debbugs-gnu-implicit-ids))’

In end of data:
lib/debbugs/debbugs-gnu.el:2927:1:Warning: the following functions are not
    known to be defined: if-let*, blockers, string-replace