Fixing a pointer mismatch: it was introduced when I moved the common code code to upload (header/write callback) to a distinct function.
Fixing a pointer mismatch: it was introduced when I moved the common
code code to upload (header/write callback) to a distinct function.

This commit fixes a potential memory leak (since the client code of
'common_upload' would not receive its correct pointer to cleanup).

Adenilson/libgcal,mback2k/libgcal,Adenilson/libgcal