Fix error handling in pjsua_create() and pjsua_init()

[nanang]

Reported that application crashes on releasing its memory pool after pjsua_init returning error. After investigation, we found that pjsua_destroy() is automatically called by pjsua_init() upon failure, so calling any PJ API after that may lead to crash.

This ticket will fix the following issues:

• pjsua_init() shouldn't call pjsua_destroy() upon failure
• also pjsua_create() should reset all pjsua states (including pjlib's) upon failure.

Thanks Yeffry Zakizon for the report.

[nanang]

In 4861:

Close #1772: Fixed error handling in pjsua_create() and pjsua_init().