Only run non-sys checks on the CI if the crate actually exists

.gitlab-ci.yml

@@ -197,6 +197,7 @@ plugins-update-nightly:
       # Keep features in sync with below
     - |
       for crate in gstreamer*; do
+        if [ -e $crate/Cargo.toml ]; then
           if [ -n "$ALL_FEATURES" ]; then
             if [ $crate = "gstreamer" ]; then
               FEATURES=ser_de,v1_18
@@ -212,6 +213,7 @@ plugins-update-nightly:
             cargo build --locked --color=always --manifest-path $crate/Cargo.toml
             G_DEBUG=fatal_warnings cargo test --color=always --manifest-path $crate/Cargo.toml
           fi
+        fi
       done
 
       # If we do a build with all features then also build the
@@ -274,6 +276,7 @@ clippy:
       # Keep features in sync with above
     - |
       for crate in gstreamer*; do
+        if [ -e $crate/Cargo.toml ]; then
           if [ $crate = "gstreamer" ]; then
             FEATURES=ser_de,v1_18
           elif [ $crate = "gstreamer-gl" ]; then
@@ -283,6 +286,7 @@ clippy:
           fi
 
           cargo clippy --locked --color=always --manifest-path $crate/Cargo.toml --features=$FEATURES --all-targets -- -A clippy::redundant_pattern_matching -A clippy::single_match -A clippy::cast_lossless -A clippy::missing_safety_doc -D warnings
+        fi
       done
     # And also run over all the examples/tutorials
     - |