Treat Seccomp failures as fatal errors.

The return value of SetUpMinijail is not being checked.
media.codec and media.extractor should not run without Seccomp if
there's a policy.

Bug: 34723744
Test: media.codec, media.extractor start, have Seccomp.
Test: cat /proc/`pgrep .codec`/status | grep Seccomp
      Seccomp:    2
Test: cat /proc/`pgrep .extractor`/status | grep Seccomp
      Seccomp:    2

Change-Id: I30c59d3193b3ebc8beace221741889afa2bbc8ae