glib-2.0: Fix g_key_file_load_from_* bindings
glib-2.0: Fix g_key_file_load_from_* bindings

KeyFile.load_from_file, load_from_dirs and load_from_data_dirs may
also throw FileError in addition to KeyFileError. Fixes bug 582517.

GNOME/vala,frida/vala,tjol/vala-tjol,frida/vala,flobrosch/vala-fixes,jessevdk/vala,jessevdk/vala,lovebug356/vala,GNOME/vala,severinh/vala,Distrotech/vala,Distrotech/vala,themiwi/vala,rvu95/vala,GNOME/vala,severinh/vala,xdave/pvala,kamanashisroy/aroop,themiwi/vala,rvu95/vala,playya/vala,frida/vala,kamanashisroy/aroop,GNOME/vala,tjol/vala-tjol,themiwi/vala,spidermonkdust/vala,Jc2k/vala,phako/vala,phako/vala,severinh/vala,frida/vala,rvu95/vala,frida/vala,kamanashisroy/aroop,spidermonkdust/vala,spidermonkdust/vala,lovebug356/vala,Jc2k/vala,playya/vala,Distrotech/vala,playya/vala,flobrosch/vala-fixes,jessevdk/vala,flobrosch/vala-fixes,tjol/vala-tjol