ahcsrc: failed to run repeated playing and paused actions

Submitted by Justin Kim @joykim

Link to original bug (#763308)

Description

When "sync" property is set as "false", the pipeline seems to work well.
However, if sync is true on sink element, the pipeline including ahcsrc fails to change state to PLAYING.

Reproducible sequence:

• Run android camera example apps (#760963) - need to confirm sync property is true
• Repeat click paused and play

Then

• Cannot transit to playing state

Tested on Nexus 5x and LG V410 (I am not sure if this error is occurred in other devices)