fix POPPLER_NOT_0_20_0 check

0.20x is affected, not only 0.20. I think this should be checked
here only, though if it was 100% sure a poppler bug. But this
is at least better to the broken check before..

Change-Id: If01a4329d18d317371be11d63c66b3487f5f556b

configure.in

@@ -9704,8 +9704,8 @@ if test "x$enable_ext_pdfimport" != "xno" -a "x$enable_extension_integration" !=
       SYSTEM_POPPLER=YES
       PKG_CHECK_MODULES( POPPLER, poppler >= 0.8.0 )
       # sdext test fails with 0.20.0
-      PKG_CHECK_MODULES( POPPLER_NOT_0_20_0, poppler != 0.20.0,
-        , [AC_MSG_ERROR([Poppler 0.20.0 is broken, do not use --with-system-poppler or use a different version])])
+      PKG_CHECK_MODULES( POPPLER_NOT_0_20_0, poppler < 0.20.0,
+        , [AC_MSG_ERROR([Poppler 0.20.x is broken, do not use --with-system-poppler or use a different version])])
       AC_LANG_PUSH([C++])
       save_CXXFLAGS=$CXXFLAGS
       save_CPPFLAGS=$CPPFLAGS