Fix some warnings, one of which was a legit bug.

[zturner]

Summary

MSVC warns that not all control paths return a value when a switch
doesn't have a default case handler.  Changed explicit value checks
to a default check.

Also, it caught a case where bitwise AND was being used instead of
logical AND.  I'm not sure what this fixes, but presumably it is
not covered by any kind of test case.

[jasonmolenda]

Nice catch on the UnwindAssembly bug, thanks.. LazyBools only have three possible states (and aren't going to gain extra states in the future) so the code in CommandInterpreter was safe - but silencing warnings is always good to do so we can spot real issues. Thanks.

include/lldb/Interpreter/CommandInterpreter.h

     {
         switch (flag)
         {
-            case eLazyBoolCalculate:
-            case eLazyBoolYes:
-                return true;
             case eLazyBoolNo:
                 return false;
+            default:
+                return true;
         }
     }
 

         {
             case eLazyBoolYes:
                 return true;
-            case eLazyBoolCalculate:
-            case eLazyBoolNo:
+            default:
                 return false;
         }
     }

source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp

             {
                 ret_insn_offset = m_func_bounds.GetByteSize() - 6;
             }
-            else if (bytebuf[0] == 0x5d && bytebuf[1] == 0xc3 
-                     && bytebuf[2] == 0x0f && bytebuf[3] == 0x1f & bytebuf[4] == 0x44) // mov & ret & nop
+            else if (bytebuf[0] == 0x5d && bytebuf[1] == 0xc3
+                     && bytebuf[2] == 0x0f && bytebuf[3] == 0x1f && bytebuf[4] == 0x44) // mov & ret & nop
             {
                 ret_insn_offset = m_func_bounds.GetByteSize() - 6;
             }