Fix strip_prefix

Fixes #221.

--
MOS_MIGRATED_REVID=104499510
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
index 295a833..87688c7 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
@@ -81,9 +81,9 @@
     try {
       AggregatingAttributeMapper mapper = AggregatingAttributeMapper.of(rule);
       String prefix = null;
-      if (mapper.has("rm_path_prefix", Type.STRING)
-          && !mapper.get("rm_path_prefix", Type.STRING).isEmpty()) {
-        prefix = mapper.get("rm_path_prefix", Type.STRING);
+      if (mapper.has("strip_prefix", Type.STRING)
+          && !mapper.get("strip_prefix", Type.STRING).isEmpty()) {
+        prefix = mapper.get("strip_prefix", Type.STRING);
       }
       decompressed = (DecompressorValue) env.getValueOrThrow(
           DecompressorValue.key(rule.getTargetKind(), rule.getName(),
diff --git a/src/test/shell/bazel/external_integration_test.sh b/src/test/shell/bazel/external_integration_test.sh
index b0c709b..638d88a 100755
--- a/src/test/shell/bazel/external_integration_test.sh
+++ b/src/test/shell/bazel/external_integration_test.sh
@@ -512,7 +512,7 @@
     name = "x",
     url = "http://localhost:$nc_port/x.tar.gz",
     sha256 = "$sha256",
-    rm_path_prefix = "x/y/z",
+    strip_prefix = "x/y/z",
     build_file = "x.BUILD",
 )
 EOF