dovecot: Include cli-based tests in the coverage tests

Many areas of the dovecot library are tested via chamuyero scripts, but
these were not being included in the coverage report.

This patch extends the dovecot-auth-cli tests so that they are now
coverage-aware.

cmd/dovecot-auth-cli/coverage_test.go

@@ -0,0 +1,33 @@
+// This package is tested externally (see test.sh).
+// However, we need this to do coverage tests.
+//
+// See coverage_test.go for the details, this is the same horrible hack.
+//
+// +build coveragebin
+
+package main
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+	"testing"
+)
+
+func TestRunMain(t *testing.T) {
+	done := make(chan bool)
+
+	signals := make(chan os.Signal, 1)
+	go func() {
+		<-signals
+		done <- true
+	}()
+	signal.Notify(signals, os.Interrupt, os.Kill, syscall.SIGTERM)
+
+	go func() {
+		main()
+		done <- true
+	}()
+
+	<-done
+}