Add missing ? to specfile variable.

Signed-off-by: Avi Miller <avi.miller@oracle.com>

hack/make/.build-rpm/docker-engine.spec

@@ -105,7 +105,7 @@ for deploying and scaling web apps, databases, and backend services without
 depending on a particular stack or provider.
 
 %prep
-%if 0%{?centos} <= 6 || 0%{oraclelinux} <=6
+%if 0%{?centos} <= 6 || 0%{?oraclelinux} <=6
 %setup -n %{name}
 %else
 %autosetup -n %{name}