Fix working directory for Appveyor

Author: liufengyun

.appveyor.yml

@@ -5,17 +5,23 @@ install:
   - cmd: SET PATH=C:\sbt\bin;%JAVA_HOME%\bin;%PATH%
   - cmd: SET SBT_OPTS=-XX:MaxPermSize=2g -Xmx4g
 clone_script:
+  - pwd
+  - ls
   - git clone --depth 50 https://github.com/lampepfl/dotty.git
   - cd dotty
-  - git submodule update --init --recursive --jobs 3
+  - git submodule update --init --recursive --depth 50 --jobs 3
 build_script:
-  - project/scripts/sbt compile
-  - project/scripts/sbt "dotty-bootstrapped/compile"
+  - pwd
+  - ls
+  - ./project/scripts/sbt compile
+  - ./project/scripts/sbt "dotty-bootstrapped/compile"
 test_script:
-  - project/scripts/sbt test
-  - project/scripts/cmdTests
-  - project/scripts/sbt "dotty-bootstrapped/test"
-  - project/scripts/bootstrapCmdTests
+  - pwd
+  - ls
+  - ./project/scripts/sbt test
+  - ./project/scripts/cmdTests
+  - ./project/scripts/sbt "dotty-bootstrapped/test"
+  - ./project/scripts/bootstrapCmdTests
 cache:
   - C:\sbt\
   - C:\Users\appveyor\.ivy2