adb: configure /system file permission with fs_config

adbd changes the permissions of files uploaded by copying
owner's permission to group and other. This causes kernel
load failure if any changes are made to kernel modules
followed by ``adb push'' or ``adb sync'' because file mode
644 would become 666.

The change uses fs_config to get the target mode of files.

In addition, the SELinux file label is set incorrectly
on synced files. Set the label properly.

Change-Id: I354db848f39adfbf189d7e8d3b028e8d763c772f
Signed-off-by: Liang Cheng <licheng@nvidia.com>
Bug: 12264775
adb: do not chown/chmod files pushed to sdcard

Commit "adb: configure /system file permission with fs_config" can cause
'Operation not permitted' errors when pushing files to sdcard because
chown and chmod are not allowed. Omit chown and chmod operations if the
destination directory has sdcard in the group name.

Change-Id: I05767a2699b152392b4ff1606194826285cbcb1e
adbd: Don't close/reopen FFS ep0 on disconnect

In case of bulk read/write failure or disconnect, transport_usb
calls usb_ffs_kick in order to force the daemon to re-open the
FunctionFS ep files as a way to soft restart the kernel driver.

However, there's no reason to always close the ep0 file, as it
would need to be reopened and the descriptors rewritten--this
is unnecessary, especially in the simple/frequent case of cable
disconnect, and causes the kernel driver to unbind and bind *all*
of the function drivers. This is causing USB Chapter 9 tests to fail.

Thus, try to reuse the same ep0 file handle across reconnects. In
case there is a failure, the ep1/ep2 opens would fail and all the
file handles get dropped. For the adb root case, the entire daemon
gets restarted anyway.

CRs-fixed: 571846
Change-Id: I0840085c52a0795dcb2d751c39aa4a436c039ee2