fix #266 ble forced to re-pair details below

The NVS copies of hte BLE pairing info for clients were getting corrupted
occasionally.  So I went googling and found some plausible bug reports
but nothing that was an exact match.  Then I looked at the arduino-esp32
binaries for the ESP-IDF framework.  They were fairly old (Jan 20).

Looking through the commits on ESP-IDF release3.3 it seems like there have
been a few fixes for mutual exclusion errors wrt bluetooth.  So I punted
and tried updating ESP-IDF to latest and everything seems fairly solid
now.  Currently running a long test run with three nodes.

platformio.ini

@@ -90,7 +90,7 @@ build_flags =
 # board_build.ldscript = linker/esp32.extram.bss.ld
 lib_ignore = segger_rtt
 platform_packages =
-    framework-arduinoespressif32 @ https://github.com/meshtastic/arduino-esp32.git#71ed4002c953d8c87f44ed27e34fe0735f99013e
+    framework-arduinoespressif32 @ https://github.com/meshtastic/arduino-esp32.git#7a78d82f1b5cf64715a14d2f096b8dd775948ac1
 
 ; The 1.0 release of the TBEAM board
 [env:tbeam]