qga-win: Fix build_guest_fsinfo() close of nonexistent

On the current error path of build_guest_fsinfo(), a non existent handle
is passed to CloseHandle().

This patch adds initialization of hLocalDiskHandle to
INVALID_HANDLE_VALUE, and checks for handle validity before the handle
is closed.

Signed-off-by: Basil Salman <basil@daynix.com>
Signed-off-by: Basil Salman <basil@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>

qga/commands-win32.c

@@ -1091,7 +1091,7 @@ static GuestFilesystemInfo *build_guest_fsinfo(char *guid, Error **errp)
     size_t len;
     uint64_t i64FreeBytesToCaller, i64TotalBytes, i64FreeBytes;
     GuestFilesystemInfo *fs = NULL;
-    HANDLE hLocalDiskHandle = NULL;
+    HANDLE hLocalDiskHandle = INVALID_HANDLE_VALUE;
 
     GetVolumePathNamesForVolumeName(guid, (LPCH)&mnt, 0, &info_size);
     if (GetLastError() != ERROR_MORE_DATA) {
@@ -1149,7 +1149,9 @@ static GuestFilesystemInfo *build_guest_fsinfo(char *guid, Error **errp)
     fs->type = g_strdup(fs_name);
     fs->disk = build_guest_disk_info(guid, errp);
 free:
-    CloseHandle(hLocalDiskHandle);
+    if (hLocalDiskHandle != INVALID_HANDLE_VALUE) {
+        CloseHandle(hLocalDiskHandle);
+    }
     g_free(mnt_point);
     return fs;
 }