gen-egg-recipes: add CHICKEN major version to URI paths

Egg tarballs are now split according to the CHICKEN major version,
since they tend to be incompatible.

Signed-off-by: Mario Domenech Goulart <mario@ossystems.com.br>
Update all egg recipes' SRC_URI to point to the right path for CHICKEN 4

With the upcoming CHICKEN 5 release, the egg tarballs location have
been split according to the CHICKEN major version (4 and 5).  So, add,
/4 to recipes' SRC_URI paths.

Signed-off-by: Mario Domenech Goulart <mario@ossystems.com.br>