Remove abort from FcCompareSize.

There doesn't appear to be a good reason to abort when 'v1' has type
FcTypeRange. If there does turn out to be a good reason for this then it
should be better documented and the code for handling this case removed.
At worst it seems -1 should be returned as it is for other unknown
types. It is possible this is left over debug code from the initial
implementation.
diff --git a/src/fcmatch.c b/src/fcmatch.c
index df6db71..53c3b0e 100644
--- a/src/fcmatch.c
+++ b/src/fcmatch.c
@@ -235,7 +235,6 @@
         b1 = e1 = value1.u.d;
 	break;
     case FcTypeRange:
-	abort();
 	b1 = value1.u.r->begin;
 	e1 = value1.u.r->end;
 	break;