gstvalue: preserve parse behaviour with warning

Preserve the previous behaviour where:
    name, val="5";
passed to gst_structure_from_string would have resulted in an int value,
rather than a string, despite the quote marks.

This will be changed to being interpreted as a string in the future, but
for the time being we will issue a warning about this to give users time
to fix their code to no longer rely on this bug.
29 jobs for clean_up_serialization in 107 minutes and 45 seconds (queued for 17 seconds)
Status Job ID Name Coverage
  Preparation
passed #923796
gst indent

00:00:50

passed #923795
manifest

00:00:42

 
  Build
passed #923807
build cerbero cross-android universal

00:11:46

manual #923812
gst-ios-12.2 allowed to fail manual
build cerbero cross-ios universal
passed #923808
build cerbero cross win32

00:09:35

passed #923810
build cerbero cross win64

00:04:18

passed #923806
build cerbero fedora x86_64

00:06:24

passed #923811
gst-macos-10.14
build cerbero macos x86_64

00:06:07

passed #923801
build clang fedora x86_64

00:10:25

passed #923797
build fedora x86_64

00:06:30

passed #923805
docker windows 1607
build msys2

00:16:08

passed #923798
build nodebug fedora x86_64

00:04:44

passed #923799
build static fedora x86_64

00:12:06

passed #923800
build static nodebug fedora x86_64

00:06:11

passed #923802
docker windows 1607
build vs2017 amd64

00:14:10

passed #923804
docker windows 1607
build vs2017 x86

00:14:19

 
  Test
passed #924771
gstreamer
check fedora

00:03:37

passed #923814
gstreamer
integration testsuites fedora

00:40:34

passed #923819
gstreamer
valgrind bad

00:07:45

passed #923816
gstreamer
valgrind base

00:07:33

passed #924772
gstreamer
valgrind core

00:08:34

passed #923820
gstreamer
valgrind ges

00:06:31

passed #923817
gstreamer
valgrind good

00:08:57

passed #923818
gstreamer
valgrind ugly

00:02:08

failed #923813
gstreamer
check fedora

00:03:44

failed #923815
gstreamer
valgrind core

00:09:12

 
  Integrate
passed #923821
cross-android universal examples

00:07:32

manual #923823
gst-ios-12.2 allowed to fail manual
cross-ios universal examples
passed #923822
documentation

00:02:59