qemumonitortestutils: Fix line counting in qemuMonitorTestProcessFileEntries()

It just so happens that our JSON snippets in
qemucapabilitiesdata/*.replies files are separated by an empty
line. These empty lines are then overwritten to make a single
line JSON. Nevertheless, the line counter @line is not
incremented which then leads to a misleading numbers in errors.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

tests/qemumonitortestutils.c

@@ -1302,6 +1302,9 @@ qemuMonitorTestProcessFileEntries(char *inputstr,
             continue;
         }
 
+        /* We've seen a new line, increment the counter */
+        line++;
+
         /* Cut off a single reply. */
         *(tmp + 1) = '\0';