[devops] Run shellcheck on all files, and fix any issues. (#16508)

tools/devops/Makefile

@@ -52,7 +52,7 @@ all check: check-sh check-yaml
 
 check-sh:
 	$(Q) if ! type shellcheck >/dev/null; then echo "shellcheck is not installed. Install it like this: 'brew install shellcheck'"; exit 1; fi
-	$(Q) shellcheck *.sh
+	$(Q) shellcheck $(shell find . -name '*.sh')
 
 check-yml check-yaml:
 	$(Q) if ! type yamllint >/dev/null; then echo "yamllint is not installed. Install it like this: 'brew install yamllint'"; exit 1; fi

tools/devops/automation/scripts/bash/build-nugets.sh

@@ -6,7 +6,7 @@ if test -z "$XAM_TOP"; then
     exit 1
 fi
 
-cd $XAM_TOP
+cd "$XAM_TOP"
 
 DOTNET_NUPKG_DIR=$(make -C tools/devops print-abspath-variable VARIABLE=DOTNET_NUPKG_DIR | grep "^DOTNET_NUPKG_DIR=" | sed -e 's/^DOTNET_NUPKG_DIR=//')
 

tools/devops/automation/scripts/bash/vsts-compare.sh

@@ -3,10 +3,10 @@
 # the yaml takes care of that.
 export WORKSPACE="$BUILD_ARTIFACTSTAGINGDIRECTORY"
 echo "GH PR: $PR_ID"
-cd $XAM_TOP
+cd "$XAM_TOP"
 
 if [[ $PR_ID ]]; then
-    git fetch --no-tags --progress https://github.com/xamarin/xamarin-macios +refs/pull/$PR_ID/*:refs/remotes/origin/pr/$PR_ID/*
+    git fetch --no-tags --progress https://github.com/xamarin/xamarin-macios "+refs/pull/$PR_ID/*:refs/remotes/origin/pr/$PR_ID/*"
 
     # Compute the correct base hash to use for comparison by getting the merge base between the target branch and the commit we're building.
     if MERGE_BASE=$(git merge-base "$SYSTEM_PULLREQUEST_SOURCECOMMITID" "refs/remotes/origin/$SYSTEM_PULLREQUEST_TARGETBRANCH"); then