Merge #398 by ted-xie: Don't provide a default adb path

The default path prevents the $PATH search logic in the broker library from functioning.

This should obviate #350, as long as users have `adb` somewhere in $PATH.
Closes #398

COPYBARA_INTEGRATE_REVIEW=#398 from ted-xie:no_default_adb aef38a6
PiperOrigin-RevId: 791322866
Change-Id: I3f1c75fa8027a4a59d85670b62cb08f92ae1736a

Author: ted-xie

src/tools/mi/deployment/deploy_binary.go

@@ -33,7 +33,7 @@ import (
 
 var (
 	adbArgs        = flags.NewStringList("adb_arg", "Options for the adb binary.")
-	adbPath        = flag.String("adb", "/usr/bin/adb", "Path to the adb binary to use with mobile-install.")
+	adbPath        = flag.String("adb", "", "Path to the adb binary to use with mobile-install.")
 	device         = flag.String("device", "", "The adb device serial number.")
 	javaHome       = flag.String("java_home", "", "Path to JDK.")
 	launchActivity = flag.String("launch_activity", "", "Activity to launch via am start -n package/.activity_to_launch.")