For an empty file, the interface (eg. webdav) could ask to create with data=None. Allow that. bzr revid: p_christ@hol.gr-20100623140709-m11r40kk2dl9okvo
To be done: ----------- * Test to not create several times the same file / directory -> May be put a sql_constraints uniq on several files -> test through remove or put * Retest everything