Move modem_set_carrier to crosh from crosh-workarounds

bin/crosh

Index: bin/crosh
diff --git a/bin/crosh b/bin/crosh
index ec237c5711f887276d074de75248d9b4049cfdd1..60fb850aa4033a2e670b3c4546f9cc1adad3fe2f 100755
--- a/bin/crosh
+++ b/bin/crosh
@@ -54,6 +54,9 @@ HELP='
  modem <command> [args...]
   Interact with the 3G modem. Run "modem help" for detailed help.
 
+ modem_set_carrier carrier-name
+  Configures the modem for the specified carrier.
+
  network_logging <wifi | cellular | ethernet>
   A function that enables a predefined set of tags useful for
   debugging the specified device.
@@ -409,6 +412,10 @@ cmd_modem() {
   /usr/bin/modem "$@"
 }
 
+cmd_modem_set_carrier() {
+  /usr/bin/modem_set_carrier "$@"
+}
+
 cmd_set_apn() {
   /usr/bin/set_apn "$@"
 }