test: Pass -q to grep command to suppress matched output

debian/changelog

@@ -161,6 +161,7 @@ dpkg (1.18.11) UNRELEASED; urgency=medium
     - Skip the involved tests if IO::String is missing.
     - Add new unit test for libdpkg error handling.
     - Delete MAKEFLAGS environment variable when testing make invocations.
+    - Pass -q to grep command to suppress matched output in pod-coverage.t.
   * Build system:
     - Add support for profiling perl modules.
     - Clean up compiler and linker automatic flag usage in configure.

t/pod-coverage.t

@@ -35,7 +35,8 @@ sub all_pod_modules
         return unless $module =~ s/\.pm$//;
 
         # As a first step just check public modules (version > 0.xx).
-        return unless system('grep', '^our \$VERSION = \'[^0]\.', $File::Find::name) == 0;
+        return unless system('grep', '-q', '^our \$VERSION = \'[^0]\.',
+                                     $File::Find::name) == 0;
 
         $module =~ s{^\Q$File::Find::topdir\E/}{};