clover: Add constructor for global_argument.

Fix defects reported by Coverity Scan.

member_not_init_in_gen_ctor: The compiler-generated constructor for this class does not initialize buf.
member_not_init_in_gen_ctor: The compiler-generated constructor for this class does not initialize svm.

Signed-off-by: Vinson Lee <vlee@freedesktop.org>
36 jobs for !8623 with fix-cid-1213936 in 14 seconds (queued for 3 seconds)
detached
Status Job ID Name Coverage
  Sanity
passed #6797048
sanity

00:00:14

 
  Container
manual #6797051
aarch64 manual
arm_build
manual #6797052
manual
arm_test-base
manual #6797053
windows shell 1809 mesa manual
windows_build_vs2019
manual #6797049
manual
x86_build-base
manual #6797050
manual
x86_test-base
 
  Container 2
created #6797061
android_build
created #6797064
arm64_test
created #6797065
armhf_test
created #6797058
i386_build
created #6797054
kernel+rootfs_amd64
created #6797055
aarch64
kernel+rootfs_arm64
created #6797056
aarch64
kernel+rootfs_armhf
created #6797059
ppc64el_build
created #6797060
s390x_build
created #6797057
x86_build
created #6797062
x86_test-gl
created #6797063
x86_test-vk
 
  Meson X86 64
created #6797071
meson-clang
created #6797072
meson-clover
created #6797068
meson-clover-testing
created #6797069
meson-gallium
created #6797070
meson-release
created #6797066
meson-testing
created #6797067
meson-testing-asan
created #6797073
meson-vulkan
 
  Build Misc
created #6797074
meson-android
created #6797076
aarch64
meson-arm64
created #6797077
aarch64
meson-arm64-build-test
created #6797075
aarch64
meson-armhf
created #6797079
meson-i386
created #6797082
meson-mingw32-x86_64
created #6797081
kvm
meson-ppc64el
created #6797080
kvm
meson-s390x
created #6797078
allowed to fail
scons-win64
 
  Software Renderer
created #6797083
llvmpipe-piglit-cl