glx: Stop specifying GLX_DEPTH_SIZE

This code is just confused. It's asking for at least as many bits of
(z-axis) depth as the root window has bits of (color) depth. For rgb565
or rgb888 this is harmless, but at 10 bits per channel this demands a
30-bit or deeper Z buffer. While some hardware could in principle do a
32-bit Z buffer, Mesa does not expose such fbconfigs (at least on Intel
and AMD).

We're not actually using the Z buffer, so just stop asking for one.
11 jobs for <span class="ref-name">no-glx-depth-size</span> in 18 minutes and 3 seconds (queued for 1 second)
Status Job ID Name Coverage
  Preparation
passed #121672
gst indent

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passed #121671
manifest

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  Build
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build fedora x86_64

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  Test
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check fedora

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  Full Builds
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build android arm64 api28

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build cerbero cross win32

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build cerbero cross win64

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build cerbero fedora x86_64

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build cerbero cross win32

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build cerbero cross win64

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build cerbero fedora x86_64

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