cmake: copy qt version requirements from autotools

Set versions 4.8.0 and 5.2.0 as minimal required for Qt4 and Qt5.

src/CMakeLists.txt

@@ -23,7 +23,7 @@ if (QT5)
     if (DBUS)
         list (APPEND QBT_QT_COMPONENTS DBus)
     endif (DBUS)
-    find_package(Qt5 5.5.0 COMPONENTS ${QBT_QT_COMPONENTS} REQUIRED)
+    find_package(Qt5 5.2.0 COMPONENTS ${QBT_QT_COMPONENTS} REQUIRED)
 else (QT5)
     list(APPEND QBT_QT_COMPONENTS QtCore QtNetwork QtXml)
     if (GUI)
@@ -32,7 +32,7 @@ else (QT5)
     if (DBUS)
         list (APPEND QBT_QT_COMPONENTS QtDBus)
     endif (DBUS)
-    find_package(Qt4 4.8.7 COMPONENTS ${QBT_QT_COMPONENTS} REQUIRED)
+    find_package(Qt4 4.8.0 COMPONENTS ${QBT_QT_COMPONENTS} REQUIRED)
     include(${QT_USE_FILE})
 endif (QT5)