[Patch] Angle.cpp: fix gcc6 build

[mt]

Gcc6 warns '-Werror=misleading-indentation', so I reindent source code.

C++ /home/haiku/haiku/haiku/generated-gcc6/objects/haiku/x86/release/servers/app/Angle.o 
/home/haiku/haiku/haiku/src/servers/app/Angle.cpp: In member function 'Angle Angle::Constrain180()':
/home/haiku/haiku/haiku/src/servers/app/Angle.cpp:228:5: error: this 'if' clause does not guard... [-Werror=misleading-indentation]
     if (value < 0)
     ^~
/home/haiku/haiku/haiku/src/servers/app/Angle.cpp:230:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
  return Angle(value);
  ^~~~~~
/home/haiku/haiku/haiku/src/servers/app/Angle.cpp: In member function 'Angle Angle::Constrain90()':
/home/haiku/haiku/haiku/src/servers/app/Angle.cpp:245:5: error: this 'if' clause does not guard... [-Werror=misleading-indentation]
     if (value < 0)
     ^~
/home/haiku/haiku/haiku/src/servers/app/Angle.cpp:247:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
  return Angle(value);
  ^~~~~~
cc1plus: all warnings being treated as errors

[waddlesplash]

Applied in hrev50308. Thanks!