Updating hammer script based on review suggestions.

hammer

Index: hammer
===================================================================
--- hammer	(revision 23335)
+++ hammer	(working copy)
@@ -11,10 +11,10 @@
 # Explicitly skip site_scons directories that are from the 'software
 # construction toolkit', since these are not gyp compatible.
 SRC_DIR=`pwd`
-while `test ! -d "${SRC_DIR}/site_scons" -o \
-       -e "${SRC_DIR}/site_scons/site_tools/component_setup.py"`; do
-  PARENT_DIR="$(dirname ${SRC_DIR})"
-  if `test "${SRC_DIR}" = "${PARENT_DIR}"`; then
+while [ ! -d "${SRC_DIR}/site_scons" ] || \
+      [ -e "${SRC_DIR}/site_scons/site_tools/component_setup.py" ]; do
+  PARENT_DIR="$(dirname "${SRC_DIR}")"
+  if [ "${SRC_DIR}" = "${PARENT_DIR}" ]; then
     echo "ERROR: hammer must be run in a directory with site_scons under" >&2
     echo "       the root of the project tree." >&2
     exit 1