[coretext] Use intended coretext version check logic (#315)

diff --git a/src/hb-coretext.cc b/src/hb-coretext.cc
index e68ee91..507581b 100644
--- a/src/hb-coretext.cc
+++ b/src/hb-coretext.cc
@@ -152,7 +152,8 @@
    * operating system versions. Except for the emoji font, where _not_
    * reconfiguring the cascade list causes CoreText crashes. For details, see
    * crbug.com/549610 */
-  if (&CTGetCoreTextVersion != NULL && CTGetCoreTextVersion() <= kCTVersionNumber10_9) {
+  // 0x00070000 stands for "kCTVersionNumber10_10", see CoreText.h
+  if (&CTGetCoreTextVersion != NULL && CTGetCoreTextVersion() < 0x00070000) {
     CFStringRef fontName = CTFontCopyPostScriptName (ct_font);
     bool isEmojiFont = CFStringCompare (fontName, CFSTR("AppleColorEmoji"), 0) == kCFCompareEqualTo;
     CFRelease (fontName);