dist/azure-coverage.yml: remove a now-unneeded line

Author: pkgw

dist/azure-coverage.yml

@@ -53,7 +53,6 @@ steps:
 # support in the test harness to wrap the invocations in `kcov` calls.
 - bash: |
     set -xeuo pipefail
-    p="$(pwd)"
     export TECTONIC_EXETEST_KCOV_RUNNER="kcov --include-path=$(pwd) --exclude-pattern=/tests/"
     cargo test --test executable
   displayName: Special-case executable tests