sys-cluster/glusterfs: enable LTO, disable O3

LTO is enabled by default for debian builds, and is now safe to enable.
O3 produces segfault when mounting a volume.

sys-config/ltoize/files/package.cflags/lto.conf

@@ -83,7 +83,6 @@ sys-apps/fwupd *FLAGS-=-flto* # Issue #225, LTO causes runtime failures
 sys-apps/man-db *FLAGS-=-flto* # Issue #403, LTO causes runtime failures
 sys-apps/nix *FLAGS-=-flto* # Issue #222, LTO causes runtime failures
 sys-cluster/ceph *FLAGS-=-flto*  # linking error during compilation
-sys-cluster/glusterfs *FLAGS-=-flto* # undefined reference to `glfs_subvol_done'
 sys-devel/clang *FLAGS-=-flto* # Issue #619 Same as above
 sys-devel/gdb *FLAGS-=-flto*
 sys-devel/llvm *FLAGS-=-flto* # Issue #619 temporarily disabled for now due to build errors
@@ -176,4 +175,5 @@ x11-libs/wxGTK NOLDADD=1 C*FLAGS-="-Wl,*" # Issue #40, does not build when -Wl l
 # BEGIN: Misc Workarounds
 dev-lang/ruby *FLAGS+=-fno-strict-aliasing # No build or runtime failures, but recommended by the package to avoid incorrect optimizations
 sys-libs/compiler-rt-sanitizers *FLAGS+=-Wno-unused-command-line-argument # Test failure
+sys-cluster/glusterfs *FLAGS-=-O3* # Segfault.
 # END: Misc Workarounds