Removed unneeded function declaration.

src/runner_doiact_vec.c

@@ -27,7 +27,6 @@
 /* This object's header. */
 #include "runner_doiact_vec.h"
 
-void runner_dopair1_density(struct runner *r, struct cell *ci, struct cell *cj);
 #ifdef WITH_VECTORIZATION
 /**
  * @brief Compute the vector remainder interactions from the secondary cache.
@@ -1373,7 +1372,6 @@ void runner_dopair1_density_vec(struct runner *r, struct cell *ci,
     } /* loop over the parts in cj. */
     
     TIMER_TOC(timer_dopair_density);
-
   }
 
 #endif /* WITH_VECTORIZATION */