Fix crash in llvm-objdump with -macho -objc-meta-data that was trying dump a non-existent section.

Showed up in running on a large binary with the missing section.  I could create a fake
test case if anyone really wants but the fix is pretty obvious.

rdar://25837034


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267037 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed