Fix typo in document

Bug: None
Test: N/A
Change-Id: I5839a2f90b57e2ac08d2de16d1b792babce4b2c7
diff --git a/microdroid/README.md b/microdroid/README.md
index 91371b5..e1af9be 100644
--- a/microdroid/README.md
+++ b/microdroid/README.md
@@ -67,7 +67,7 @@
 $ adb shell 'cd /data/local/tmp/microdroid; /apex/com.android.virt/bin/mk_cdisk /apex/com.android.virt/etc/microdroid_cdisk.json os_composite.img'
 $ adb shell 'cd /data/local/tmp/microdroid; /apex/com.android.virt/bin/mk_cdisk /apex/com.android.virt/etc/microdroid_cdisk_env.json env_composite.img'
 $ adb shell 'cd /data/local/tmp/microdroid; /apex/com.android.virt/bin/mk_cdisk /apex/com.android.virt/etc/microdroid_cdisk_userdata.json userdata_composite.img'
-$ adb shell '/apex/com.android.virt/bin/crosvm create_qcow2 --backing_file=/data/local/tmp/microdroid/userdata_composite.img /data/local/tmp/microdroid/userdata_composite.$ qcow2'
+$ adb shell '/apex/com.android.virt/bin/crosvm create_qcow2 --backing_file=/data/local/tmp/microdroid/userdata_composite.img /data/local/tmp/microdroid/userdata_composite.qcow2'
 $ adb shell 'cd /data/local/tmp/microdroid; /apex/com.android.virt/bin/mk_payload /apex/com.android.virt/etc/microdroid_payload.json payload.img'
 $ adb shell 'chmod go+r /data/local/tmp/microdroid/*-header.img /data/local/tmp/microdroid/*-footer.img'
 $ adb push microdroid.json /data/local/tmp/microdroid/microdroid.json