Merge pull request #4294 from leidwang/issue3461

fwcfg: update command to make it more accurate and general

Author: vivianQizhu

qemu/tests/cfg/fwcfg.cfg

@@ -6,7 +6,7 @@
     vmcoreinfo = yes
     start_vm = no
     tmp_dir = "/var/tmp"
-    get_avail_disk = df -h /home | grep home | awk -F "G" '{print $3}'
+    get_avail_disk = df -BG /home | awk 'NR==2 {print $4}' | sed 's/G//'
     unzip_cmd = 'powershell -command "Expand-Archive %s:\Memory.dmp.zip %s:"'
     unzip_timeout = 1800
     dump_file = Memory.dmp

qemu/tests/cfg/fwcfg_enable.cfg

@@ -9,7 +9,7 @@
     start_vm = no
     setup_verifier = no
     tmp_dir = "/home/tmp"
-    get_avail_disk = df -h /home | grep home | awk -F "G" '{print $3}'
+    get_avail_disk = df -BG /home | awk 'NR==2 {print $4}' | sed 's/G//'
     unzip_cmd = 'powershell -command "Expand-Archive %s:\Memory.dmp.zip %s:"'
     unzip_timeout = 1800
     dump_file = Memory.dmp

qemu/tests/cfg/win_virtio_driver_update_test.cfg

@@ -288,7 +288,7 @@
             device_name = "QEMU FwCfg Device"
             device_hwid = '"ACPI\VEN_QEMU&DEV_0002"'
             tmp_dir = "/home/tmp"
-            get_avail_disk = df -h /home | grep home | awk -F "G" '{print $3}'
+            get_avail_disk = df -BG /home | awk 'NR==2 {print $4}' | sed 's/G//'
             unzip_cmd = 'powershell -command "Expand-Archive %s:\Memory.dmp.zip %s:"'
             unzip_timeout = 1800
             dump_file = Memory.dmp