test1139: make it display the difference on test failures

tests/data/test1139

@@ -15,13 +15,19 @@ documentation
 none
 </server>
 
- <name>
+<name>
 Verify that all libcurl options have man pages
- </name>
+</name>
 
 <command type="perl">
 %SRCDIR/manpage-scan.pl %SRCDIR/.. %PWD/..
 </command>
 </client>
 
+<verify>
+<stderr>
+0
+</stderr>
+</verify>
+
 </testcase>

tests/manpage-scan.pl

@@ -288,4 +288,4 @@ foreach my $o (keys %opts) {
     }
 }
 
-exit $errors;
+print STDERR "$errors\n";