msdk: ignore MFX_ERR_UNDEFINED_BEHAVIOR when loading a plugin

An issue can be seen when using msdkh265enc with bitrate change in
playing state. The root cause is the corresponding plugin is loaded
again.

Returning MFX_ERR_UNDEFINED_BEHAVIOR from MSDK just means the plugin has
been loaded, so we may ignore this error when doing configuation again
in the sub class, otherwise the pipeline will be interrupted
22 jobs for msdk-ignore-load-failure in 90 minutes and 54 seconds (queued for 27 minutes and 20 seconds)
latest
Status Job ID Name Coverage
  Preparation
passed #902255
gst indent

00:00:30

passed #902254
manifest

00:00:40

 
  Build
passed #902265
build cerbero cross-android universal

00:15:20

manual #902269
gst-ios-12.2 allowed to fail manual
build cerbero cross-ios universal
passed #902266
build cerbero cross win32

00:05:38

passed #902267
build cerbero cross win64

00:05:38

passed #902264
build cerbero fedora x86_64

00:05:22

passed #902268
gst-macos-10.14
build cerbero macos x86_64

00:11:02

passed #902260
build clang fedora x86_64

00:08:09

passed #902256
build fedora x86_64

00:05:31

passed #902263
docker windows 1607
build msys2

00:16:39

passed #902257
build nodebug fedora x86_64

00:05:55

passed #902258
build static fedora x86_64

00:11:50

passed #902259
build static nodebug fedora x86_64

00:04:22

passed #902261
docker windows 1607
build vs2017 amd64

00:14:36

passed #902262
docker windows 1607
build vs2017 x86

00:15:27

 
  Test
passed #902270
check fedora

00:03:43

passed #902271
integration testsuites fedora

00:39:31

passed #902272
valgrind bad

00:06:01

 
  Integrate
passed #902273
cross-android universal examples

00:07:06

manual #902275
gst-ios-12.2 allowed to fail manual
cross-ios universal examples
passed #902274
documentation

00:04:17