Current error message does not provide the exact path where the
Dockerfile is being searched.
This commit distinguishes two types of errors when Dockerfile is not
found in build context:
- when the context does not have provided custom-named Dockerfile, the
path in the error message is absolute: "OSError: Dockerfile not found in
.../podman-compose/tests/integration/build_fail/context_no_file/custom-named-Dockerfile"
- when the context does not have any Dockerfile, the path in the error
message is: "OSError: Dockerfile not found in
.../podman-compose/tests/integration/build_fail/context_no_file"
Only this error message was used before the fix.
Signed-off-by: Monika Kairaityte <monika@kibit.lt>
Co-authored-by: Siteshwar Vashisht <svashisht@redhat.com>