Add DESTDIR for installing f-spot's libdir
Add DESTDIR for installing f-spot's libdir

When using DESTDIR variable in "make install", f-spot tries to install
the libdir to '$(libdir)/f-spot' which completely ignores the $(DESTDIR)
given and attempts to install in e.g. /usr/lib/f-spot, which is not the desired
folder and requires root privileges.

-- Rafael Ferreira

mans0954/f-spot,Yetangitu/f-spot,mono/f-spot,Sanva/f-spot,Sanva/f-spot,mans0954/f-spot,Sanva/f-spot,Yetangitu/f-spot,dkoeb/f-spot,mono/f-spot,mans0954/f-spot,NguyenMatthieu/f-spot,NguyenMatthieu/f-spot,dkoeb/f-spot,mono/f-spot,dkoeb/f-spot,mans0954/f-spot,dkoeb/f-spot,Yetangitu/f-spot,mans0954/f-spot,mono/f-spot,mono/f-spot,dkoeb/f-spot,NguyenMatthieu/f-spot,Yetangitu/f-spot,mans0954/f-spot,mono/f-spot,NguyenMatthieu/f-spot,dkoeb/f-spot,Yetangitu/f-spot,NguyenMatthieu/f-spot,Sanva/f-spot,Sanva/f-spot