Fixed compiler warning in npc_barnacle: operator '?:' has lower precedence than '+'; '+' will be evaluated first [-Wparentheses]

Fixed order of operations based on code comment: // digest poisonous things for just a moment before being killed by them (it looks wierd if it's instant)

This changes the order of operations.

--

Building on Mac OS X 10.8.4, Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)

REDACTED/sp/src/game/server/hl2/npc_barnacle.cpp:1813:63: warning: operator '?:' has lower precedence than '+'; '+' will be evaluated first [-Wparentheses]
  m_flDigestFinish = gpGlobals->curtime + m_bSwallowingPoison ? 0.48f : 10.0f;
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
REDACTED/sp/src/game/server/hl2/npc_barnacle.cpp:1813:63: note: place parentheses around the '+' expression to silence this warning
  m_flDigestFinish = gpGlobals->curtime + m_bSwallowingPoison ? 0.48f : 10.0f;
                                                              ^
                     (                                       )
REDACTED/sp/src/game/server/hl2/npc_barnacle.cpp:1813:63: note: place parentheses around the '?:' expression to evaluate it first
  m_flDigestFinish = gpGlobals->curtime + m_bSwallowingPoison ? 0.48f : 10.0f;
                                                              ^
                                          (                                  )