package/heimdal: security bump to version 7.4.0

package/heimdal: security bump to version 7.4.0

Fixes security bugs CVE-2017-11103 & CVE-2017-6594

Changed upstream tarball location as noted in the release notes:
http://www.h5l.org/releases.html?show=7.4.0

--with-db-type-preference= is needed to fix a build error:

  CCLD     otp
../../lib/otp/.libs/libotp.a(otp_db.o): In function `otp_get_internal':
otp_db.c:(.text+0x32): undefined reference to `__roken_dbm_fetch'
otp_db.c:(.text+0xd9): undefined reference to `__roken_dbm_store'
../../lib/otp/.libs/libotp.a(otp_db.o): In function `otp_db_open':
otp_db.c:(.text+0x1c9): undefined reference to `__roken_dbm_open'
../../lib/otp/.libs/libotp.a(otp_db.o): In function `otp_db_close':
otp_db.c:(.text+0x205): undefined reference to `__roken_dbm_close'
../../lib/otp/.libs/libotp.a(otp_db.o): In function `otp_delete':
otp_db.c:(.text+0x23e): undefined reference to `__roken_dbm_delete'
../../lib/otp/.libs/libotp.a(otp_db.o): In function `otp_put':
otp_db.c:(.text+0x388): undefined reference to `__roken_dbm_store'
collect2: error: ld returned 1 exit status

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>