spec: fix indentation

The recent specfile addition broke syntax-check:
cppi: ../libvirt.spec.in: line 338: not properly indented
cppi: ../libvirt.spec.in: line 341: not properly indented
cppi: ../libvirt.spec.in: line 344: not properly indented

Fixes: ac063cb2Signed-off-by: NJán Tomko <jtomko@redhat.com>

libvirt.spec.in

@@ -335,13 +335,13 @@ BuildRequires: device-mapper-devel
 # For XFS reflink clone support
 BuildRequires: xfsprogs-devel
 %if %{with_storage_rbd}
-%if 0%{?fedora} || 0%{?rhel} > 7
-BuildRequires: librados-devel
-BuildRequires: librbd-devel
-%else
-BuildRequires: librados2-devel
-BuildRequires: librbd1-devel
-%endif
+    %if 0%{?fedora} || 0%{?rhel} > 7
+        BuildRequires: librados-devel
+        BuildRequires: librbd-devel
+    %else
+        BuildRequires: librados2-devel
+        BuildRequires: librbd1-devel
+    %endif
 %endif
 %if %{with_storage_gluster}
 BuildRequires: glusterfs-api-devel >= 3.4.1