Updates to expect_match

change order of positional params to match that of grep
fix bug that prevented output of usage when run without opts
reformat usage statement to be more readable

Change-Id: Ib51d35367543e217d78d0748787b8220026bace4

setup.sh

diff --git a/setup.sh b/setup.sh
index 08c3fd1..5a5d39b 100644
--- a/setup.sh
+++ b/setup.sh
@@ -329,20 +329,20 @@
 ## Watch a file for a pattern and exit when matched or timed out
 function expect_match
 {
-    local log_path="$(realpath $1)"
-    local match_string="$2"
+    local match_string="$1"
+    local log_path="$2"
     local timeout="$3"
 
-    local usage="Usage: expect_match <file path> <pattern> [timeout]
-    filepath: Path to file to search
-    pattern: grep regexp pattern
-    timeout: optional timeout, defaults to 30s"
-
-    if [[ -z "${log_path}" ]]; then
-        echo usage
+    if [[ -z "${match_string}" ]] || [[ -z "${log_path}" ]]; then
+        echo "Usage: expect_match <pattern> <file path> [timeout]"
+        echo "    pattern: grep regexp pattern"
+        echo "    file path: Path to file to search"
+        echo "    timeout: optional timeout, defaults to 30s"
         return 1
     fi
 
+    log_path="$(realpath ${log_path})"
+
     if [[ -z "${timeout}" ]]; then
         timeout="30s"
     fi