Do not recycle logical vectors when indexing into edge/vertex selectors

[szhorvat]

With @krlmlr's agreement, the following behaviour is undesirable:

> g <- make_ring(5) # graph with 5 vertices
> V(g)[c(T,F)] # recycles, completing the vector to T,F,T,F,T
+ 3/5 vertices, from 4cd3034:
[1] 1 3 5

Reasoning:

Suppose that we have a graph g and a modified version g2. Then we try to select some vertices of g based on properties of g2, like so: V(g)[ V(g2)$foo > 2 ]. If g and g2 have a different number of vertices, this should ideally result in an error. Right now it does not, due to recycling.