Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
config(gdm)
gdm
gdm(x86-32)
gdm-libs(x86-32)
gdm-plugin-fingerprint
gdm-plugin-smartcard
libgdm.so.1
service(graphical-login)

Requires :

config(gdm) = 1:3.14.2-20.el7_3
libgobject-2.0.so.0
systemd => 186
libpthread.so.0
gnome-settings-daemon => 2.21.92
libaccountsservice.so.0
libaudit.so.1
rtld(GNU_HASH)
libgdk_pixbuf-2.0.so.0
libcanberra.so.0
libcanberra-gtk3.so.0
libc.so.6(GLIBC_2.4)
gnome-shell => 3.14.2
pulseaudio-gdm-hooks
libselinux.so.1
gnome-keyring-pam
libgio-2.0.so.0
libc.so.6(GLIBC_2.1.3)
rpmlib(PayloadIsXz) <= 5.2-1
libXau => 1.0.4-4
gnome-session
libgtk-3.so.0
accountsservice
pam => 0:0.99.8.1-11
libc.so.6(GLIBC_2.2)
libc.so.6(GLIBC_2.0)
libc.so.6(GLIBC_2.1.2)
audit-libs => 1.0.6
/usr/sbin/useradd
/bin/sh
libXdmcp.so.6
libpthread.so.0(GLIBC_2.0)
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
libpam.so.0(LIBPAM_1.0)
libc.so.6(GLIBC_2.3)
libsystemd.so.0
libXau.so.6
libpam.so.0
libX11.so.6
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(CompressedFileNames) <= 3.0.4-1
libsystemd.so.0(LIBSYSTEMD_209)
xorg-x11-xinit
system-logos
xorg-x11-server-utils
libgdk-3.so.0
libc.so.6(GLIBC_2.1)
libgdm.so.1
systemd
setxkbmap
libxcb.so.1
libglib-2.0.so.0
dconf
/sbin/nologin
libc.so.6
iso-codes
libc.so.6(GLIBC_2.3.4)

Content of RPM :
/etc/dbus-1/system.d/gdm.conf
/etc/dconf/db/gdm.d
/etc/dconf/db/gdm.d/locks
/etc/gdm
/etc/gdm/Init
/etc/gdm/Init/Default
/etc/gdm/PostLogin
/etc/gdm/PostLogin/Default.sample
/etc/gdm/PostSession
/etc/gdm/PostSession/Default
/etc/gdm/PreSession
/etc/gdm/PreSession/Default
/etc/gdm/Xsession
/etc/gdm/custom.conf
/etc/pam.d/gdm-autologin
/etc/pam.d/gdm-fingerprint
/etc/pam.d/gdm-launch-environment
/etc/pam.d/gdm-password
/etc/pam.d/gdm-pin
/etc/pam.d/gdm-smartcard
/run/gdm
/usr/bin/gdm-screenshot
/usr/bin/gdmflexiserver
/usr/lib/girepository-1.0/Gdm-1.0.typelib
/usr/lib/libgdm.so
/usr/lib/libgdm.so.1
/usr/lib/libgdm.so.1.0.0
/usr/lib/systemd/system/gdm.service
/usr/libexec/gdm-host-chooser
/usr/libexec/gdm-session-worker
There is 138 files more in these RPM.