Remove use of --no-preserve=mode argument to 'cp'

This is not supported on OSX and is currently breaking
the mac build.

Review URL: https://codereview.chromium.org/1563353002
diff --git a/ports/gtest/build.sh b/ports/gtest/build.sh
index 0390f22..2a7debb 100644
--- a/ports/gtest/build.sh
+++ b/ports/gtest/build.sh
@@ -78,10 +78,8 @@
   local srcdir=${DESTDIR}/${PREFIX}/src
   MakeDir ${srcdir}/gtest/include
 
-  LogExecute cp -r --no-preserve=mode ${SRC_DIR}/include/gtest \
-    ${srcdir}/gtest/include/gtest
-
-  LogExecute cp -r --no-preserve=mode ${SRC_DIR}/src ${srcdir}/gtest
+  LogExecute cp -r ${SRC_DIR}/include/gtest ${srcdir}/gtest/include/gtest
+  LogExecute cp -r ${SRC_DIR}/src ${srcdir}/gtest
 }
 
 TestStep() {