Bind once expressions with leading spaces are failing the parsing

[cexbrayat]

Playing with the bind once feature in 1.3-beta.10, I ran into the following issue. The code :

<div>{{ ::name }}</div>

throws the error :

Error: [$parse:syntax] Syntax Error: Token ':' not a primary expression at column 2 of the expression [ ::name ] starting at [::name ].

The error is due to the leading space in the expression.