esx: Fix regression in absolute file name handling

Before commit 145d6cb05c (in August 2010) absolute file names
in VMX and domain XML configs were handled correctly. But this got
lost during the refactoring. The test cases didn't highlight this
problem because they have their own set of file name handling
functions. The actual ones require a real connection to an ESX
server. Also the test case functions always worked correctly.

Fix the regression and add a new in-the-wild VMX file that contains
such a problematic absolute path. Even though this test case won't
protect against new regressions.

Reported by lofic (IRC nick)

tests/xml2vmxdata/xml2vmx-esx-in-the-wild-6.vmx

@@ -0,0 +1,26 @@
+.encoding = "UTF-8"
+config.version = "8"
+virtualHW.version = "4"
+guestOS = "other-64"
+uuid.bios = "56 4d 15 d4 d0 62 fe 9a-80 f5 eb 8e 1a 2c 3a fc"
+displayName = "el6-test"
+memsize = "1024"
+numvcpus = "1"
+scsi0.present = "true"
+scsi0.virtualDev = "pvscsi"
+scsi0:0.present = "true"
+scsi0:0.deviceType = "scsi-hardDisk"
+scsi0:0.fileName = "/vmfs/volumes/datastore/directory/el6-test-000001.vmdk"
+ide1:0.present = "true"
+ide1:0.deviceType = "cdrom-image"
+ide1:0.fileName = "/usr/lib/vmware/isoimages/linux.iso"
+floppy0.present = "false"
+floppy1.present = "false"
+ethernet0.present = "true"
+ethernet0.virtualDev = "vmxnet3"
+ethernet0.networkName = "VM Network"
+ethernet0.connectionType = "bridged"
+ethernet0.addressType = "generated"
+ethernet0.generatedAddress = "00:0C:29:2C:3A:FC"
+ethernet0.generatedAddressOffset = "0"
+svga.vramSize = "8388608"