[librest] build: Set explicit version requirement on libsoup

[Christophe Fergeau <teuf src gnome org>]

commit 9ed72ed968fee4ca258ac1e376fd84d4595747b0
Author: Christophe Fergeau <cfergeau redhat com>
Date:   Tue Jul 19 13:09:54 2016 +0200

    build: Set explicit version requirement on libsoup
    
    We switched to using SoupSession directly, but it's only possible since
    libsoup 2.42

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4d92dfc..24b5eeb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -41,7 +41,7 @@ LT_PREREQ([2.2.6])
 LT_INIT([disable-static])
 
 PKG_CHECK_MODULES(GLIB, glib-2.0 >= 2.38)
-PKG_CHECK_MODULES(SOUP, libsoup-2.4)
+PKG_CHECK_MODULES(SOUP, libsoup-2.4 >= 2.42)
 PKG_CHECK_MODULES(XML, libxml-2.0)
 PKG_CHECK_MODULES(GTHREAD, gthread-2.0)