[guile] fix post scriptlet to not remove files on upgrade

[Miroslav Lichvar]

commit 1c1745664f9c2f89ff3502ac363d73d32ff6421d
Author: Miroslav Lichvar <mlichvar at redhat.com>
Date:   Tue Jul 16 18:18:39 2013 +0200

    fix post scriptlet to not remove files on upgrade

 guile.spec |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)
---
diff --git a/guile.spec b/guile.spec
index 04fbd94..6e86c5d 100644
--- a/guile.spec
+++ b/guile.spec
@@ -106,8 +106,18 @@ if [ "$1" = 0 ]; then
             %{_infodir}/dir &> /dev/null
     done
 fi
-rm -f %{_bindir}/guile
-rm -f %{_bindir}/guile-tools
+:
+
+%triggerin -- guile < 5:2.0.9-3
+# Allow safe upgrade from older versions
+ln -f %{_bindir}/guile{,.save}
+ln -f %{_bindir}/guile-tools{,.save}
+:
+
+%posttrans
+# Move saved files back
+[ -e %{_bindir}/guile.save ] && mv -f %{_bindir}/guile{.save,}
+[ -e %{_bindir}/guile-tools.save ] && mv -f %{_bindir}/guile-tools{.save,}
 :
 
 %triggerin -- slib