rpm_5.4.9.bb: fix builds on systems with older libc

rpm_5.4.9.bb: fix builds on systems with older libc

| dbconvert.o: In function `rpmdb_convert':
| /local/jenkins/jobs/yocto-upstream/workspace/label/master/machine/p4080ds/poky/master/tmp/work/x86_64-linux/rpm-native-5.4.9-r45/rpm-5.4.9/tools/dbconvert.c:126: warning: the use of `tempnam' is dangerous, better use `mkstemp'
| dbconvert.o: In function `main':
| dbconvert.c:(.text+0x923): undefined reference to `htobe32'
| dbconvert.c:(.text+0xaa4): undefined reference to `htole32'
| dbconvert.c:(.text+0xac9): undefined reference to `htole32'

(From OE-Core rev: add2c772cd404e8bea4828959fcb5ee33c35c048)

Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>