Fix memory leak in TurboVNC

Note that the memory leak was only occurring with the colorspace
emulation code, which is only active when using regular libjpeg (not
libjpeg-turbo.)

Diagnosed by Christian Beier, using valgrind.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

common/turbojpeg.c

@@ -601,7 +601,7 @@ DLLEXPORT int DLLCALL tjCompress2(tjhandle handle, unsigned char *srcBuf,
 	bailout:
 	if(cinfo->global_state>CSTATE_START) jpeg_abort_compress(cinfo);
 	#ifndef JCS_EXTENSIONS
-	if(rgbBuf && rgbBuf!=srcBuf) free(rgbBuf);
+	if(rgbBuf) free(rgbBuf);
 	#endif
 	if(row_pointer) free(row_pointer);
 	return retval;
@@ -835,7 +835,7 @@ DLLEXPORT int DLLCALL tjDecompress2(tjhandle handle, unsigned char *jpegBuf,
 	bailout:
 	if(dinfo->global_state>DSTATE_START) jpeg_abort_decompress(dinfo);
 	#ifndef JCS_EXTENSIONS
-	if(rgbBuf && rgbBuf!=dstBuf) free(rgbBuf);
+	if(rgbBuf) free(rgbBuf);
 	#endif
 	if(row_pointer) free(row_pointer);
 	return retval;