[strongswan] fix prerelease logic

[Pavel Šimerda]

commit 66b5f0bde7f84884321cb796a9e3b31e10cccba4
Author: Pavel Šimerda <psimerda at redhat.com>
Date:   Thu Jul 17 09:27:41 2014 +0200

    fix prerelease logic

 strongswan.spec |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/strongswan.spec b/strongswan.spec
index 3bdda4f..75799ff 100644
--- a/strongswan.spec
+++ b/strongswan.spec
@@ -96,7 +96,7 @@ possessing a standard IF-IMC/IMV interface. In addition, it implements
 PT-TLS to support TNC over TLS.
 
 %prep
-%setup -q -n %{name}-%{version}%{prerelease}
+%setup -q -n %{name}-%{version}%{?prerelease}
 #%patch1 -p1
 
 echo "For migration from 4.6 to 5.0 see http://wiki.strongswan.org/projects/strongswan/wiki/CharonPlutoIKEv1" > README.Fedora