mpkg: extract last occurence only from index.
mpkg: extract last occurence only from index.

Execution may breaks if many occurences (ie. versions) of packages exist in
the index. Assuming taking the last occurence (tail -n1) while the applet is
not yet able to compare version of packages.

Signed-off-by: Gaël PORTAY <1666f60cfa201a60b0ea694168a0b6932673170a@gmail.com>

gazoo74/mpkg,gazoo74/mpkg