Fixes the following error.
gstccconverter.c:677:7: error: variable 'len' is used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
if (flags & 0x40) {
^~~~~~~~~~~~
gstccconverter.c:698:10: note: uninitialized use occurs here
return len;
^~~
gstccconverter.c:677:3: note: remove the 'if' if its condition is always true
if (flags & 0x40) {
^~~~~~~~~~~~~~~~~~
gstccconverter.c:572:12: note: initialize the variable 'len' to silence this warning
guint len;
^
= 0
