spec: Fix indentation

Commit ffc49e579c broke syntax-check:

  cppi: libvirt.spec.in: line 622: not properly indented
  cppi: libvirt.spec.in: line 624: not properly indented
  cppi: libvirt.spec.in: line 640: not properly indented
  cppi: libvirt.spec.in: line 642: not properly indented
  maint.mk: incorrect preprocessor indentation
  cfg.mk:697: recipe for target 'sc_spec_indentation' failed

Indent the new conditionals properly.

(cherry picked from commit 55d8daa07e)

libvirt.spec.in

@@ -917,9 +917,9 @@ Requires: gzip
 Requires: bzip2
 Requires: lzop
 Requires: xz
-%if 0%{?fedora} >= 24
+            %if 0%{?fedora} >= 24
 Requires: systemd-container
-%endif
+            %endif
 
 %description daemon-driver-qemu
 The qemu driver plugin for the libvirtd daemon, providing
@@ -935,9 +935,9 @@ Group: Development/Libraries
 Requires: libvirt-daemon = %{version}-%{release}
 # There really is a hard cross-driver dependency here
 Requires: libvirt-daemon-driver-network = %{version}-%{release}
-%if 0%{?fedora} >= 24
+            %if 0%{?fedora} >= 24
 Requires: systemd-container
-%endif
+            %endif
 
 %description daemon-driver-lxc
 The LXC driver plugin for the libvirtd daemon, providing