Improve previous commit

Resolves: #1977428

djvulibre-3.5.27-out-of-bound-write-2.patch

@@ -7,7 +7,7 @@ index 60a4f39..b11df7b 100644
    char *buffer = textUTF8.getbuf(textsize);
    int readsize = bs.read(buffer,textsize);
 -  buffer[readsize] = 0;
-+  if (readsize > 0)
++  if (buffer)
 +    buffer[readsize] = 0;
    if (readsize < textsize)
      G_THROW( ERR_MSG("DjVuText.corrupt_chunk") );

djvulibre.spec

@@ -3,7 +3,7 @@
 Summary: DjVu viewers, encoders, and utilities
 Name: djvulibre
 Version: 3.5.27
-Release: 29%{?dist}
+Release: 30%{?dist}
 License: GPLv2+
 URL: http://djvu.sourceforge.net/
 Source0: http://downloads.sourceforge.net/djvu/%{name}-%{version}.tar.gz
@@ -195,6 +195,10 @@ fi
 
 
 %changelog
+* Fri Jul 02 2021 Marek Kasik <mkasik@redhat.com> - 3.5.27-30
+- Improve previous commit
+- Resolves: #1977428
+
 * Fri Jul 02 2021 Marek Kasik <mkasik@redhat.com> - 3.5.27-29
 - Fix out-of-bounds write in djvutext
 - Resolves: #1977428