ui: Drop minimum version to match RHEL7

And add unit test to catch future dependency issues

tests/misc.py

@@ -89,3 +89,27 @@ class TestMisc(unittest.TestCase):
         files += _find_py("virtcli")
 
         self._check_modules(files)
+
+
+    def test_ui_minimum_version(self):
+        import glob
+        import xml.etree.ElementTree as ET
+        failures = []
+        for filename in glob.glob("ui/*.ui"):
+            root = ET.parse(filename).getroot()
+
+            req = root[0]
+            if req.tag != "requires":
+                continue
+
+            if req.attrib.get("lib") != "gtk+":
+                continue
+            version = req.attrib["version"]
+            if (int(version.split(".")[0]) > 3 or
+                int(version.split(".")[1]) > 8):
+                failures.append((filename, req.attrib["version"]))
+
+        if failures:
+            raise AssertionError("The following files require a gtk version "
+                "higher than our target of gtk-3.8:\n" +
+                "\n".join([("%s version=%s" % tup) for tup in failures]))

ui/addstorage.ui

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- Generated with glade 3.16.1 -->
 <interface>
-  <requires lib="gtk+" version="3.10"/>
+  <requires lib="gtk+" version="3.8"/>
   <object class="GtkAdjustment" id="adjustment1">
     <property name="upper">1000000</property>
     <property name="step_increment">0.10000000000000001</property>

ui/gfxdetails.ui

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- Generated with glade 3.16.1 -->
 <interface>
-  <requires lib="gtk+" version="3.10"/>
+  <requires lib="gtk+" version="3.8"/>
   <object class="GtkAdjustment" id="adjustment4">
     <property name="lower">5900</property>
     <property name="upper">50000</property>

ui/netlist.ui

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- Generated with glade 3.16.1 -->
 <interface>
-  <requires lib="gtk+" version="3.10"/>
+  <requires lib="gtk+" version="3.8"/>
   <object class="GtkGrid" id="net-source-box">
     <property name="visible">True</property>
     <property name="can_focus">False</property>